Another vote for Tire Rack, and a vote for National Tire and Battery (NTB). My local
NTB will price-match anything on Tire Rack, so I do my research online and then get the tires from NTB. I feel a little dirty for not directly supporting Tire Rack, but if you buy tires from NTB then you get lifetime rotations for free. Plus they are always having other specials.
As to tire size, I once got wider tires on my old Subaru and the upgrade in handling was impressive. Gas mileage suffered, though. Then when they wore out and I went back to the original size, it felt a little bit like I was on bicycle tires at first ...
