Find a good solid one that is completely flat... My worst one was this red translucent one I got with a wrist pad. I think not being solid caused some of my mice to loose where they were and throw the cursor all over the screen. Then, the edges were higher than the pad. That cased the mouse to lift up just enough to break contact with the laser(or just mess my movement up)
They have these massivly expensive gamming pads, but you know, as long as you have a good solid surface, you'd be fine.