For college use, you need something reliable but not flashy. You don't want to attract fhieves.
In college, I used my old Sears 3-speed. Nothing flashy, but I had it set up to fit me perfectly, along with some performance enhancements like toe clips and drop bars. It helped that I was on the cross-country and wrestling teams, so I had power to burn. Surprised the college cycling club when they held a 5 mile "race" as part of homecoming. Beat all of them on their fancy 10-speeds.
When my niece went to college, she came to me for a bike. I garbage picked an old Schwinn Varsity, stripped it down to the individual ball bearings and put it back together in perfect running order, then made her sit through a couple hours of fitting and adusting so seat height, etc., were just right for her. Spray painted it in rustoleum brown and avocado green camouflage. Looked like crap (not attractive to thieves...), ran great. Lasted her all four years. Her friends called it "the Jeep". Oddly enough, she joined the Army out of college.
There are a lot of reasons your dad's mountain bike might've felt awkward. Maybe its a piece of crap from Walmart (No offense, but you didn't mention brand or model). Maybe it was set up for him, not you. Like shoes, fit on a bike can make a world of difference. Even if his bike is a really nice one, the wrong frame size and setup can make it ride like a pig.
To give you an idea, this is my daily driver: http://www.flickr.com/photos/silverbullet1952/5198414684/in/photostream
Capable of decent speed, yet it can handle almost any terrain. I have other bikes for racing (triathlon mostly) or fast group rides.
I think, for your purposes, a decent mountain bike, or hybrid would be the best choice. If you, or someone you know, knows their way around a wrench, crank puller, and chain whip (special bike tool), a used or garbage picked bike that doesn't look like much would be ideal