Hi Robert,
What I practiced when I was at college and what I practice now are pretty much the same (give or take a few clever tricks that I spent ages working on at college that never got me anywhere...

) - I work on the fundementals. I work on my timing, my tone, my knowledge of the fingerboard and how it relates to harmony and I work on my ear. The context changes a lot - sometimes I'll be working on a specific exercise and just do it as slowly as I can to focus on what each note is about. Other times, I'll set up some kind of ambient loop in order to put the exercise in some context. I often practice playing through jazz standards, playing a walking line, the melody, a solo and comping the chords, trying to get inside the changes, working on where the key changes in the song, etc.
I think it's important to keep working on this stuff. It's never ending. When I was at college, the guitar tutor would sit during his lunch hour playing over ii V I progressions in band in a box, working on new phrases, new ideas, new ways of approaching the same stuff he'd be playing for years.
Occasionally I spend some time on a new technique, if there's something I've come across that I want to try out, and most of my practice time turns into composition time at some point, but the initial ideas are just those basic things.
cheers!
Steve
www.stevelawson.net