A 'rolla with over 100k miles is a great buy. It's almost broken in.

Replace the water pump and timing belt and you're good to go for another 60-80k miles.
A Corolla (Geo Prism) or Camry would be a good choice. So would a Civic (gag me) or Accord. They're safe, have good fuel economy and will be dependable. The Hondas tend to retain their value more and will be more expensive. They're also not as fun to work on, in my experience.
A 240 or 700 series Volvo is a good choice, especially if you find one from, like, '87 or newer. Early 80's ones had electrical issues but aside from that, they're bulletproof. A BMW 318 or 325 is also a cheap car now that should be good for you.
I'd stay away from the plastic domestics. They aren't worth the money you save in buying one when you factor in the repairs and lifespan of the car. My first car was a Toyota Tercel. It was a gutless wonder but got me through high school and four years of college without a hitch.