Yeah it very much depends which bit you get as to whether you hit the German part, the English part or the actual island! Germans aren't so bad on holiday though, much less of a mess than the English abroad... going to Ibiza has re-structured my whole idea of the English tourist. Soller, Santanyi and Pollenca are places I've had some really nice family holidays, but we didn't exactly sample the nightlife too much beyond a drink in a bar by the sea so maybe not the best person to ask if you want to go clubbing.
I think it's really easy to go from Gibraltar into the rest of Spain. I don't even remember there being any security, but we didn't stay in Gibraltar itself - just flew in and then hired a car to go elsewhere - so can't say more than that.
EDIT: also if you go to the North, there is this amazing mountain restaurant near Lluc called Es Guix and it's worth a nauseating mountain drive to get there. They have these amazingly blue (and freezing!) plunge pools of mountain water you can swim in after lunch. It's a really unique place.