Research, my man!
Check out YeloSno's Hierarchy of Buying Paintball Equipment.
Research in the reviews section about what markers you like. For the most part, it's what fits you. Any gun out there will shoot quickly and efficiently in the right hands, but it's what you want to play with that will determine what marker you buy. Get a tank and mask first. This'll help with marker costs and stuff like that...
CSU Rams Paintball
Rocking drop-forwards like they're going out of style...oh, wait...