http://www.wowhead.com/?talent#f0eb0xZMgVo0cxqru0xRtxThere's a PvE combat build. Sinister Strike, Eviscerate, and you're good. For instances and especially bosses, keep Slice and Dice going and rupture if it's a boss. I'd level with this build until you can do Mutilate. Go down the combat tree first, then subtlety, then assasination. Grabbing Malice from assassination earlier can work too.
http://www.wowhead.com/?talent#fhecoxMoiroGzZ0xZebdbhMdbHere's a PvP Mutilate build. I'd start with
this build at level 52 (or at 50, but your mutilates will suffer a little without opportunity from the subtlety tree), then work toward the level 80 PvP mutilate build I linked.
I've leveled 2 different rogues recently (yea, I hate rerolling to join friends), and this is how I did it. Mutilate no longer requires you to be behind the target, making it much easier to level with. If you open with cheapshot and throw in a kidney shot, a lot of mobs die without you taking a single hit, meaning no downtime while leveling. Once you hit 80, those 2 builds I linked are the cookie cutter PvE (combat) and PvP (mutilate) builds for rogues right now (thought some people like to go mutilate 51/13/7 for PvE).
For stats, go for agility and attack power first, though chance to hit can help a lot while leveling since you'll be low on hit rating unless you're combat (5% hit from talents). I use Jame's
horde/alliance leveling guides when leveling to make things faster. It's all questing, so you never have to stop and grind to catch up to the levels of the quests you have available to you. (I haven't tried the addon versions yet, just the html based ones. I've used the horde guides all the way from level 1 to Grizzly Hills, and all the alliance ones except 1-60)