Outcall: Jeans and "v normal" shirt or more businessy suit, depending on location.
my personal Incall/girlfriend favorites: lingerie, Nun's outfit, Catholic School girl uniform, nurse uniform, all black leather outfit, nothing at all, geeky eyeglasses+cowboy hat and knee-hi boots (and nothing else), sunglasses+fake mustache+sandals+nothing else, 1950s vintage top and skirt, wedding dress (no underwear a must), old-fashioned stewardess (airline attendant for those born after 1980) uniform, 1960s school teacher outfit (short plaid skirt, hair pulled up a must).
Perhaps the weirdest: German Airforce Uniform top, helmet and flying glasses, nothing on the bottom.
I've gotten girlfriends to wear every single one of the above, but if anyone can help with the last one or the stewardess one, please let me know....