I'm not creative/immature enough to name my rival whatever I wanted. I think my brother called Gary "AAAAAAAAAAAAAAA" or something. I just named my rival (in Silver) "Bart". *shrugs*
In Gold I named the Rival Knuckles (after the guy from sonic, he looked like him.)
In Heart Gold I named him AxlRose (no space) the real Axl Rose is a red-headed douche, and so is your rival, so it fit.
Well, to be honest, I used to use default names until he just ticked me off, so now my rival is always named douche as a reminder why you never have a rival in a pokemon game, because they're douche bag's.
In SoulSilver, I named my rival "Phallus". I had a long history of weird names (usually swear words) after I have seen people ingame say the rival's name.
i named him "gaytard" in platinum for the hell of it. i never lost to my rival except gen 3, when GF put them in the gayest spots ever. i wish the naming rivals wasnt taken out of gen 3.
Though it does not make any sense, on my first run of Platinum I called my rival Pickle... I don't know why I just did, it still makes me snicker. Also I named him the good old fashioned Fart so your rivals mother would say "My Fart took off like a rocket as usual today."