Welcome to the site, amigo.
First up, as hilldweller said, there were no OEM 15" wheels on JK's. 16" was the size for base X (Sport in 2010+) models.
As for tires, if it's mainly on-road with some snow or dirt roads, go with an all-terrain tire. If you'll see SOME mud, I've heard GREAT things about the Dick Cepek FC II- check them out on Tirerack. Otherwise, if there's no mud involved, any old all-terrain will do. For price vs. performance, I am in love with the Firestone Destination AT's- GREAT on-road, decent off, although they're not great in mud, that's not what AT's are for. Been great in what little winter we've had up here in upstate NY so far.
I would not recommend a mud terrain on a city daily driver- it'll suck some more gas, cost more $, and not drive or last as well. Mark W.