Hey!
Me & DH went to Ibiza last summer, love, love, love it!!
Yes we may be married and slightly older than the clubbing kids (

), but Ibiza is amazing. We stayed in Playa den Bossa, which is close to the airport, and also is home to one of the superclubs on the Island "Space", and our favourite beach bar "Bora Bora".
We did venture into San Antonio a couple of nights (home to Eden and Es Paradis, as well as the sunset cafes "Cafe Del Mar" & "Mambo"), San An, is nice in the daytime and early evening, but after about 11pm, especially around "The West End" its can get really tacky.
I personally love Space as you can dance through the day rather than through the night, although DH prefers Privilege, but we both enjoyed the Water Party at Es Paradis, seriously got to been experienced to be believed!
Suggestions for resorts would be:
1) Playa Den Bossa
2) Ibiza Town
3) San Antonio
4) San Antonio Bay
All of the other resorts are really family orientated, which is nice, but if you are going looking for nightlife, you have to factor in taxi costs which can get pricey!
Pm me if you want any more info, always happy to help!