At our shop we're gearing up for winter and fixing and setting up a lot of winter bikes and I always advise people that an old bike is okay but a crappy beater isn't a good option as you have to ride the thing in harsh conditions and still want to have a nice ride.

Having your bike fail when it's -30 C isn't pretty.

My winter bike is probably too pretty to be called a beater... she was an SS last winter and is now running as a fixed gear.