Like my skiis, flyrod, and the mast of my windsurfing rig, I like the feel of something highly responsive.
A flick-ee, pick, that allows me load up the potential energy, and release it onto the next string.
While I find this mostly in the Medium catagory, I use pretty much anything in this product line:
http://www.juststrings.com/nylonstandar ... ories.html
I also have tried, and always have on hand, picks that don't bend, in the 1mm to 3mm range, and find they have a place in the gigging pick stable, typically for Env Filter work, or anything the requiers a notable high-initial-attack.
But for clean playing (meaning no effects besides reverb/deley), I just find the stiff picks to be too thud-ee sounding.
imho, A huge amount of tonal-spectrum-variance can be achieved by way of pick guage. I find this to be especially noticable on acoustic guitar.