> wireless
> trackball
Well both points were mentioned before; Wireless can cause input lag and sometimes run out of batteries while SSing freedom dive or whatever, Trackball is pretty weird/hard to play with.
Look around in some of the Mouse recommendation threads if you want to get an idea of what to get, don't forget to get a proper mousepad though.
I myself got a Mionix Naos 5000(mouse) and it's godly, and the Razer Goliathus Alpha Speed Edition(mousepad) is also nice, however I think it would've been better if I have gotten the control edition.