What kind of tire should I purchase for use on a bike trainer?
To make it easier on myself I purchased a cheap wheel on eBay and added a trainer specific tire such as the Continental Ultra Sport Hometrainer Tire. When I used regular road tires, the rubber wore out quickly. The trainer specific tire lasts much longer.

You do not want to run the trainer specific tire on the roads. So having a spare wheel with cassette makes it easier to put on your normal wheel for those nice winter days.