I went up half a size to 175/65-14, and put on Goodyear Viva 3s. Right now I probably have about 5k on them, and I like them so far. Ride is nice, they are quiet, speedo isn't off by much, and my mpg didn't suffer a great deal. They are about $55-60 each.
You are going to want to get the rear alignment squared away before putting on another set of tires, as others have said.