The World of Warcraft patch 4.3 has landed and it comes with nearly zero in the way of changes specific to any flavor of Rogue. All talents, abilities, etc. are unchanged. There is one change, but that's not really Rogue specific. Wound Poison has had its healing debuff increased to 25%. The same change was made to any similar effect, such as the Warrior's Mortal Strike.
Another change that's nice for leveling Rogues (and all other characters) is that the experience required to go from level 70 to 80 has been reduced by about a third. Not that leveling through that stretch was slow, mind you, but now you can get into the Cataclysm zones just that much faster.
Items were upgraded with the patch, as they were with all classes. There's now plenty of new gear to work for in the new dungeons and raids and to buy from the gear vendors. In addition, a paid of Legendary Daggers has been added to the game.
One interesting change that effects groups in to tanking abilities. Tank threat has been buffed nicely so it should be harder for us to pull the opposition away from the tank. Not that that was easy with a good tank, but now it's better for all tanks and allows you to worry less and just go all out.
So where do the various flavors of Rogue stand now?
For just doing damage (DPS,) all three specs are good. Each has certain strengths and weaknesses which will apply themselves differently to the various fights in the new (and old) dungeons. For PvP the story is a bit different. All are great for leveling.
Assassination is a strong DPS spec and it uses poisons to great effect, giving this spec some nice versatility. It's mostly a single target spec and is strong in PvE and good in PvP, lacking only some kind of enhanced mobility. It has very nice burst burst damage coming out of stealth and can easily maintain damage for the whole fight.
The Combat spec has strong DPS, but is weaker in PvP. It's great for running up and smashing the opposition. It has poor burst, coming out of stealth, and very consistent DPS thoughout the whole fight. The poor burst is what makes it a weaker PvP spec, but it you want to exercise your superior skills then go for it.
Subtlety is great for PvP and can do plenty of DPS in dungeons and raids, but it's a bit more complicated to play in order to generate the most damage. It does brutal damage coming out of stealth, which is one reason that it's nice for PvP. Subtlety is weaker for longer fights, but Vanish, Shadowstep, and Shadowdance make up for that to some extent.
Fortunately, in 4.3, with the increased tank abilities you won't have to worry about large bursts of damage pulling the opposition away from the tank and on to you.
As far as your gear goes the three specs are similar, but there are some differences.
For all specs main-hand weapon damage and Agility are #1 and #2. For PvP Resilience will be your #3 priority. Hit rating (to 8%) is your best secondary stat, for all specs. If you're going to use one set of gear for all things and change specs now and then, Haste is a good choice for a secondary stat.
Beyond that...
Gemming is easy, especially for Sub. Just get the red Agility gems (Delicate) and put them into all slots, regardless of socket bonuses. If you have a meta slot in your head piece, then put an Agile Shadowspirit Diamond there.
Put the Landslide enchant on both weapons, Hurricane if you need something cheaper.
Overall, Rogues in WoW are in pretty good shape and are mostly limited by your skill. This is probably why they haven't been tweaked much in the last couple of patches. Now, sneak up on something and ...