Once you own a beater, you'll always have one!
I would have to say the best beater I had was a 1990 Ford Probe GL....the base one. It was the perfect car. I could park it anywhere and not worry about getting a door ding. It didn't require any maintanence (it had 175K miles on it when I got it. It had ~205K when I donated it.) for the ~2.5 years I owned it, and since it was a hatchback, I could haul more things in it. One year I had a Christmas tree hanging out the back of it.
All that car needed was gas and oil.
I was very surprised the Probe was so reliable and it got good gas mileage. I believe the engine was built by Mazda, so that might've been something to do with it.
My recommendation when it comes to a beater; find one that is versatile i.e. has a lot of room, and has a good reliabilty track record. With that said, maybe consider a station wagon (90-97 Honda Accord and 92-96 Camry come to mind) and anything hatchback. Subaru seems to make some reliable cars, too.
A Subaru AWD wagon sounds like a great winter beater car. :dunno
What price range are you looking to spend?