Deathadder is good if you primarily play FPS, personally I'm not a fan of Logitech after owning a mx518 and G400 (just personal preference). Steelseries mouses I haven't used but have heard lots of good things about the Xai.
Depends entirely on personal preference though:
Do you play only FPS or will you need more buttons on side for MMO's?
Do you like a heavy mouse?
Hand size?
DPI?



