Hi
Another vote for the Deathadder. A mouse is a very personal thing and so you really need to try them before you buy. Before I ordered my Deathadder, I tried a Logitech G5, Razor Lachesis and Deathadder and i found the quality of the Razor mice far better than the Logitech IMHO! I bought the Deathadder as I find it great for both gaming and office/web work.
The Lachesis is very good for gaming, smoother than the Deathadder but I found it a little uncomfortable for general pc work and the G5 is a good mouse and highly rated, but I just didnt think it was made to the same quality as the Razor.
As for the diamondback and Copperhead, their very small mice which are good if you use your mouse with your fingertips rather than your palm. Doesnt suit my style but may suit you.
Just my opinion and I hope it helps.