I went to Ibiza for the Millennium...........it was absolutely amazing...........spent New Years Eve 1999 in Privilege and then New Years Day 2000 on the terrace @ Space..............the sun was beating down, the crowd was fab and the music was spot on...............I looked round and thought life doesn't get any better than this
Don't go if you are expecting it to be like in June-August, lots of places are closed but if you want to do something a bit special for the New Year then I would definitely recommend it.
I am hoping to get good info from this response as well. Some friends and I are planning on coming over from the States for New Year's. Unfortunatly we have never been [to Ibiza] before. The opportunity just presented itself. We were thinking of spending the week there and another week somewhere else in Spain.