Using Dunlop Tortex (with the turtle), I like the way they curve a bit, fits my grip better than anything else I've tried.

I seem to jump sizes from time to time depending on what and how I am playing at the moment...

Currently usng .50mm(red) for acoustic and .60mm(orange) for my electrics. I have found myself jumping up to .73(yellow) and .88(green) every now and then depending on what I am playing but the heavier picks tend to 'pop-out' of my hand due to the lack of flexbility.

Also use, in case of emergency, a little bowlers grip cream (I think it can be picked up under the name Gorilla Snot as well)- a little dab makes the pick and your fingers 'tacky' so that the pick doesn't slip.

I keep a good assortment of different picks around just to play with to make sure that I am the most comfortable that I can be.

D.