195/60R15 is stock size.
I'm running 205/50R15 Direzza Z1 Star Specs that fit very well, but are a smaller diameter then stock.
What use do you want the tire for? For the stock wheels it's hard to find good rubber, so i'd find good tires first, then see what sizes you can get. If you're just looking for general street tires, do you need a lot of rubber?
More rubber = more mechanical drag and more unsprung weight.
BTW, this should probably have been posted in the newbie section.