Definitely wood in college.
Seeing how the ball just jumps off the metal bat and whizzes by pitchers heads is freaking scary sometimes. I wasn't a pitcher during high school, and even then I was glad about that. I think it's going to take a Bryce Florie type situation (or worse) before they decide to possibly integrate wood bats in the college game.
When I was in high school obviously we used metal bats, but we also played in several wood bat tournaments and it was actually pretty fun, a nice challenge. It definitely was tougher as you don't get the bloops like you would if you were using metal, but it was a fun experience anyway.