First post here: My bike (trek 4300) that I used for getting around campus was recently stolen so I've been looking into new bikes. I have never really had any experience with hybrid bikes and such, but somebody suggested it to me. I ride my bike around campus ALL the time, ride trails sometimes, and plan on commuting to work on it (roads). Would a hybrid be a good idea for me? Somebody also said I could just put on mountain bike tires if I was going to end up doing more advanced trail stuff.

Also, can anybody give advice on decent brands/models in the $400-600 range? I'm only really used to Trek and Specialized bikes, but I'm open to anything.. is GT any good?

Thanks!