I've always just ridden on whatever tires the bike came with, and when I've got a flat, repaired it--usually creating and then having to repair at least one more flat in the process. To get the cursÚd tires off I've used pro prybars, kitchen knife handles, and, when caught short out in the boonies, even pieces of wood whittled down. For me, working on tires has always been an ordeal that seemed as though it shouldn't be anywhere near as hard as I always managed to make it.
Well, I've just swapped out knobbies for semi-slicks in about 20 minutes, first time, and without tools!
So for the three people in the BFs who have never done this before, I offer this wonderful, liberating article:
http://www.teamestrogen.com/articles/asa_levers.asp The author is an experienced pro wrench and off-road racer.