If you want lively, Magaluf is the place for you, not saying Santa Ponsa isn't, but I would rate Magaluf better.

Which month, Baben?

thanks for reply's.

thinking of going end july/begining of august!

could you recomend apartments in sp or magaluf? thanks

I have been to both Santa Ponsa and Magaluf and would say that for 18-21 year olds you will be better in Magaluf. Much more choice of bars for people your age. If you fancied a quieter night you could get a taxi or bus to SP (only about 3-4 miles away). I went to Magaluf for a week in May with my mother and the place was heaving with youngsters, but we never saw any trouble. Lots of touts trying to get you to go into their bars but they were all very good natured and helpful if you wanted directions somewhere or some other information.