Don't you go cussing my 15s!
I think 15s are worth looking for. There may be less offered, since new vehicles got goofy with wheel diameters, but I don't see the good tire companies dropping them anytime soon. But if you must change, why not go 16-17 since those are plentiful, not far off, 16" and 16.5 were original options, and they'll look better than hoola hoops. Oh yeah, almost forgot. To each their own.