i have four. back, massive shoulder piece, foot and a little one behind one ear. i do not consider this to be excessive. my best girl has a full thigh piece (it's beautiful) both feet and peacock wings wrapped around her hips. she also has a tattoo on the inside of her upper arm and one on her ribs for out friend Tom who died last year.
mine all mean something, her's not so much (apart from the obvious)
I think too much is when you have less surface area not tattooed than you do tattooed, but i'd never hold the number of tattoos someone has against them. i would judge quality and content. if you're stupid enough to get a shite tattoo or something really dodgy (like all those kids who get pissed and get "joke" tattoos) then you're just giving the rest of us a bad name. at the end of the day though, it's your body, off you go ,and unless it's actually offensive (see neo-nazi symbols, actually having swear works or sex acts tattooed on public parts of you) i have no problems with it.