I hear you British/Irish people have all but destroyed Ibiza.
The larger louts have taken a lot from the island (started by the tv show Ibiza uncovered' which was filming the first time I was there, the last really good year on the island), but if you go to the right places and know the right people its still a hell of a place. Theres the clubber parts, the scumbag chav parts and the family parts. Like most things along dance music lines, the divisions are defined by peoples character and attitudes rather than geographically i.e. an Irish clubber would have more respect over there for an english clubber than some Irish piss head causing trouble, despite the two nations troubled relationship. Thats one of the best things of the music genre, its general philosophy of peace unity and tolerance.
(BTW using the term 'british/irish' makes as much sense as using the term 'jewish/palestinian' or 'black/white person' in that context. In general, young Irish people travel on holiday, get pissed and are the life and soul of the party, young british people go away, get pissed, are loud, obnoxious, and start fights. Remember, I am saying in general.