There's so many good ones man it's difficult to choose.
Try to find one you like the size and aesthetics of, at a certain price range, they're pretty much all going to be as good as each other.
Corsair have just released a new line of RGB mice, including the M65 where it appears they've moved the 'Sniper' button closer to where your thumb will actually be. I have and love the original but that always was an issue.
As far as laser sensors go both it and the MMO-aimed M95 have one of the best on the market, also giving you freedom to move up to 8200dpi.
You can also make the choice between optical and laser, each have their advantages and disadvantages. Laser is the slightly newer tech.
I wouldn't personally recommend anything lower than the Deathadder from Razer, they have a habit of incorporating good design, bad build quality and inflated brand-driven prices.
The G400 above was one (and still is) widely regarded as one of the best gaming mice, but to my knowledge it got discontinued over a year ago and the prices are quite high. Could be wrong on that. Fortunately Logitech have released several equally good models since then.
Thermaltake make some great mice, but as always with them they're rather pricey, and the aesthetics come down to personal preference.
I like the Corsair mice, I'd like to go in for an M95 one day.
I'm also one of those people that preaches the use of a good mouse-mat, preferably hard. The glide you get is just soooo much better than anything else (like the table).