I named my first project bass Jessica. I didn't want it to be permanent at first, so I had a vinyl sticker printed and pressed that on to the clearcoat on the headstock. After two years of being my main gigging bass, the sticker still looks brand new.
I placed it on the headstock where the manufacturers logo would normally go. I wasn't going to put a "fender" sticker on it, since it technically wasn't a fender, but the headstock looked plain without any logo on it. Also, the face of the headstock doesn't get touched or man-handled too often, so the vinyl is relatively safe there (compared to other areas on the bass).