The thicker - the better, is my motto! I use Dunlop Gator 2mm, and I can't find any thicker picks around here. I can not play with thin, flimsy picks - no sir!

I want picks to have a "round" edge - not a pointy sharp edge that hits the string. This is so I get a smooth sounding tone - I can always hit the string hard to get a sharper tone.