1) how many shots do you take?

depends on if i'm on the 3 song rule or not...if i am, usually i'll have ~50 or so on my 30D, and ~100-150 on my 5D's card.  i've been to shows where i've taken a ton of photos though, over 600 shots.  and i don't usually machine gun (ie,  burst mode).

2) how many do you keep? (IE, do you delete any?)

 i never delete in the camera; the LCD can't tell the real story.

3) how many of those do you process?

i usually try to keep a gallery to ~10-20 photos per band.  sometimes i go over, but not too often.