I use to use a Razer Sidewinder (one of those models) but due to hand cramps had to give it up. I'm a fairly big guy (6'3") and my hands where to big for it.
I ended up getting the Microsoft Sidewinder mouse, which I've been pretty happy with. Its the biggest gaming mouse I could find. It has upto 2000 dpi, 2 thumb buttons, switch profiles/dpi on the fly, adjustable weights etc. It says 9, but really the L/R and clickable wheel, + 2 thumb.
i also have the microsoft sidewinder, the x8 model (newest/best) and really like it.
its a little too big for me, but not uncomfortable. its wireless, which IMO gives it a major edge over other gaming mice, and thanks to its awesome charging solution, you dont need to worry about loosing power mid-game.
the razer mamba is also very good, but its charging system is much less convinent.
the g5 is alright, but i wouldnt recomend it. its pretty mcuh just a normal mouse. it doesnt have any features thast justify the cost. the g9 is much better, but its wired.
id say check out the reviews for the razer mamba, sidewinder x8 and logitech g9 and figure out which one best suits you.