I use thumb picks which I modify by "opening" them up a bit with hot water, then I use a bit of tape to hold them securely without cutting off circulation. I play mostly finger style blues and finger style solo (Juber, Pettaway, etc.). The thumb pick gives the muffled bass the drive needed to sound like tho old timers.
To strum, I always use a flat pick ("Cool" brand Thin) ...
For Travis picking fingerstyle, I use bare flesh on thumb and minimal nails on index and middle fingers. I've tried thumb pick and various types of finger picks, but they make me feel like Edward Scissorhands ...
I find that I only feel the need to use a pick when I want some amount of speed, or volume. Because I don't have classical training, I never developed any kind of 'proper' technique. I know some guys are very fast with just their fingers, I'm not. Plus, I prefer to play with the tips of my fingers, not using the nails. Playing with other people, particularly with louder instruments like violin or banjo in a bluegrass setting, one almost has to use a pick, be it a flatpick or a thumbpick/fingerpicks to get the volume - unless you're plugged in. My main interests are jazz (standards and bossanova), bluegrass, and some folky stuff. I prefer to play with my fingers, especially when grabbing chords or playing arpeggios - I'm not very accurate with cross-picking. So, as I mentioned in the beginning of the post, I usually only turn to a pick or thumbpick/fingerpicks when I need volume or speed - it's not my first choice, or what feels most natural. I wrote a blog entry about this on my website Pick vs Fingerstyle vs Fingerpicking Guitar.
Depends on the song. Some songs just lend themselves to a flat pick while other to finger-picking. I never use a thumb pick except when playing the banjo.
Anyone else have to use a flatpick when singing? I think I need to develop some coordination. Otherwise, fingerpicking for almost everything.
Only recently have I started experimenting with hybrid stuff. It's amazing what can be done with it. 15 years playing and I'm just now "picking it up"