As Cataclysm gets nearer Rogues are looking better and better.

Assassination:

Vendetta – Marks an enemy for death increasing all damage you deal to the target by 20% and granting you unerring vision of your target regardless of concealments such as stealth and invisibility. Lasts 30 sec.

Combat

Revealing Strike – An instant attack that causes 100% of your weapon damage and increases the effectiveness of your next finishing move on that target by 20% for 15 seconds. Awards 1 combo point. Costs 40 Energy.

Patch 4.0.1 - Latest Additions

In recent builds a few additional new talents were added, and other talents were tweaked to balance out the trees. Subtlety was particularly affected as it was in need of some additional buffs Energetic Recovery – It's back! This Subtlety talent was present in some of the very early Beta builds but was subsequently removed. This talent empowers your Recuperate ability, causing its periodic effect to also restore 4 Energy per talent point. (3 points)

Find Weakness – This talent was added to the Sublety tree as a player vs. player consideration. Sub Rogues have long had a major problem dealing damage to high armor targets which made the spec useless for nearly all of Wrath of the Lich King. Find Weakness goes a long way towards removing that deficiency. The talent causes your Ambush, Garrote, and Cheap Shot abilities to reveal a flaw in your target's defenses, causing all your attacks to bypass 25% per talent point of
that enemy's armor for 10 sec. (2 points)

Coup de Grace – This talent replaced Improved Eviscerate in tier 1 of the Assassination tree, and truthfully it's a bit of a stretch to even call this a new talent. Rogues had been complaining that Eviscerate is useless for Assassination Rogues and that Improved Eviscerate had no place in the Assassination tree. In reponse, Blizzard removed the 20% Envenom damage from Vile Poisons, slapped it onto Improved Eviscerate and renamed it Coup de Grace. In the end nothing changed other than making this tier 1 talent a mandatory pickup for most specs.

Assassination:
Deadly Momentum – After killing an opponent that yields experience or honor, you have a 50% chance per talent point to increase the critical strike chance of your next attack within 10 sec by 40% and to refresh your Slice and Dice and Recuperate abilities to their original duration. (2 points)

Blackjack – Even after your Sap wears off its effects linger on enemies reducing their damage done by 35% per talent point for 8 sec. (2 points)

Improved Expose Armor – Gives a 50% chance per talent point to refund all combo points used when performing your Expose Armor ability. (2 points)

Murderous Intent – When you Backstab an enemy that is below 35% health you instantly recover 15 energy per talent point. (3 points)
Venomous Wounds – Each time your Rupture or Garrote deals damage to an enemy that is afflicted by your poison, you have a 30% chance per talent point to deal an additional X Nature damage and to regain 10 energy. (2 points)

Combat:

Improved Recuperate – Causes your Recuperate ability to restore an additional 1% per talent point of your maximum health and reduces all damage taken by 3% per talent point while your Recuperate is active. (2 points)

Reinforced Leather – Increases your armor contribution from cloth and leather by 25% per talent point. (2 points)

Restless Blades – Your finishing moves reduce the cooldown of your Adrenaline Rush, Killing Spree, and Sprint abilities by 1 sec per talent point for every combo point used in the finisher. (2 points)

Bandit’s Guile – Your Sinister Strike and Revealing Strike abilities have a 33% chance per talent point to grant you an evolved insight into your opponent’s defenses increasing damage done to that target by up to 15%. Opponents can adapt over time, negating this benefit, and striking a different opponent will begin this cycle anew. (3 points)

Subtlety:

Sanguinary Vein – Increases your damage dealt to targets with a bleed effect on them by 5% per talent point. (2 points)

Serrated Blades – Your Eviscerate has a 10% (20% with 2/2) chance per combo point to refresh your Rupture on the target to its original duration. (2 points)

Serrated Blades – Your Eviscerate has a 10% (20% with 2/2) chance per combo point to refresh your Rupture on the target to its original duration. (2 points)

Assassination received a lot of loving in the way of a simplified tree that lets them pick up all the must-have abilities and still have a couple points left over for flavor abilities. Murderous intent gives Rogues a pseudo-execute in the form of Backstab spam, this will require extensive testing to determining how worthwhile it is but it’s a step in the right direction. Venomous Wounds will also bring Rupture back into the Mutilate rotation, increasing the complexity of timer management for the spec. This is something that Rogues have been asking for since Patch 3.3. New utility abilities like Improved Expose Armor may not be perfect, but will add some flexibility to a spec that is often perceived as bringing very little to the table in terms of utility.

In designing the Combat tree Blizzard has doubled down on the philosophy of balancing the tree around cooldown abilities. Combat has more ‘filler’ talents than either of the other trees, but gets compensation deep in the tree with Restless Blades and Bandit’s Guile.

Both of these abilities represent massive DPS gains and add in some mechanics such as the Bandit’s Guile mechanic that will force Rogues to think about their rotations and targets. Improved Recuperation is also one of the big ‘must-have’ talents, particularly for PvP and is located in first tier Combat. Revealing Strike was the big new change for Combat which will force PvE and PvP Combat Rogues to have a dynamic combo point building rotation rather than mindlessly spamming Sinister Strike. This was a very welcome addition.Subtlety received very little in the way of changes. The general consensus is that Subtlety makes little sense in its current form. It doubles as the ‘finisher damage’ and bleeds tree and as the PvP mobility tree. These are not exactly complimentary abilities particularly when so much of Rogue PvP is balanced around CC that can be broken by bleeds. The tree itself was changed very little and is still loaded down with powerful cool downs. The current state of Subtlety is dismaying for most Rogues who feel like the tree is hamstrung by its powerful cooldowns which are used to justify weak overall damage for the spec. There are very few interesting PvE talents in Subtlety either and no obvious reason to select the tree for that purpose.

Updated: Analysis of Patch 4.0.1 Changes

With the addition of Find Weakness and Energetic Recovery to the Subtlety toolkit, Subtlety is shaping up to be a PvP powerhouse. Being able to regain 12 energy per tick of recuperate (works out to an additional 4 Energy per second, a 40% increase to your base regeneration) is an incredibly strong ability and will basically make it necessary to keep recuperate up all the time. That'll mean that you are running around regenerating 5% or more (depending on whether you invest in both Improved Recuperate and Quickening) every 3 seconds while generating obscene amounts of energy. That's just your survivability, lets take a look at the damage. The newly added Glyph of Hemorrhage will apply a 24 second bleed every time you use Hemo which will effectively remove the need to use Rupture to maintain the Sanguinary Vein damage bonus (though Rogues will probably opt to use Rupture anyway since they can refresh it for free via Serrated Blades) -- it's simply another way to quickly ramp up your damage versus a target.
Speaking of ramping up your damage, the damage buffs to Backstab caused

it to actually do damage. This is a new concept for Rogues that started playing in Burning Crusade or later, but Backstab can output some serious damage and when Find Weakness is properly implemented it has the potential to take Rogue physical damage to levels that haven't been seen since 3.0. All in all, Subtlety PvP right now is viable, dynamic, and will undoubtedly be the spec of choice for most Rogues in Cataclysm when it comes to player vs. player combat

Currently in 4.0.1 there isn't much to be said for Combat. The damage is horrible, using Revealing Strike is a DPS loss and it is plagued by the same mobility issues that it has faced for all of WoTLK. Until they fix the damage values this spec is a write off and should be considered incomplete.

Assassination is currently the go-to spec for PvE. Venomous Wounds and Murderous Intent weave well into a DPS cycle that juggles Rupture, Slice and Dice, and Envenom. As always, this spec demands a full range of raid buffs to be effective, but with the buff homogenization that Cataclysm is bringing this spec should fit very nicely into any raid. With the removal of Focused Attacks which used to grant the Rogue 2 Energy on every critical strike the Energy Regeneration isn't much like WoTLK. The Energy gains from Venomous Wounds and from Murderous Intent give Assassination spiky energy generation that plays more like Combat currently does. This tree is packed with PvE utility and looks to be the spec of choice for when 4.0.1 hits