Hi Karlz,
I've only been once before in 2004 and am booked up to go again in September this year.
The 2004 trip, I went with a friend and we had a fantastic time. I didn't want to come home and fell in love with the Island after my first visit. We stayed in San Antonio bay. It's a fantastic place especially for the sunsets. The clubs Eden and Es Paradis were brilliant. I did prefer Es Paradis though.
We stayed bed and breakfast so I took a lot of money out with me and I needed it. Ibiza is very expensive but worthwhile. We got the discount tickets for the clubs through Thomsons and I'm glad we did as you can expect to pay 30 to 60 Euros to get in.
This year I'm going out there with my fiance and were staying in Playa Den Bossa, half board. I have heard it is still very lively but quieter than San Antonio.
Wherever you stay in Ibiza, a visit to the Aguamar waterpark is a must. It's in Playa Den Bossa and alot of fun in the wonderful weather.
Hope this helps some how.
8)