This is my imho, but I have heard a LOT of people say DON'T level Sub... but I leveled my rogue almost primarily in the Sub talent tree because I loved alot of the talents that came with it. Is Sub the easiest way to level a rogue? Probably not, but my mantra of WoW has always been, "if it isn't fun, it must be work... and who wants to work at a game?!"

Also, once you get Shadowstep, your opener becomes just that much more devastating, which eases the longer fights and breaks some of the monotony of grinding... again, imho.

I levelled sub. It's definitely the slower, more 'patience requiring' way to level... primarily due to the need to start fights from behind the mobs. It is, however, the perfect build for levelling with a partner... while your partner keeps the mob's attention, you make it dead faster than you'd think possible :)

To answer your question... yes, you do need daggers, because your opener will be Ambush, which requires a dagger in the main hand. Rotation: Premeditation, Ambush (With Initiative), 5 point Eviscerate. Dead Mob most of the time :D

Not to be flippant, but do yourself a favor and don't level subtlety. Unless you're going to level in BG's, it's really not going to buy yourself anything useful. Combat just makes up for so many typical shortcomings that leveling characters have. If you're going to go Sub though, Edjy is right, you're going to want to go Hemo and grab a 1H sword, axe, or mace. You won't spend nearly enough time behind mobs while leveling to really use daggers.

One thing though that some people say works well, but I've never been able to make it work well for me, is that if you walk to a mob and ambush it as a sub spec, you might be able to get the mob down to like 50% and then weapon swap to a heavier weapon and Hemo it a couple times and Eviscerate. They say it's really fast, but I never make it work right.

I'd much rather have the combat enhancing and defensive talents of Combat and just grind things down more efficiently than have the flashy big numbers of Sub.

If you are leveling Sub I would suggest not going deep sub & just use either swords, axes or maces & get Hemorrhage. It would be better if you level combat though.