I went to Magaluf, and i must say it was an interesting experience, 7-8 indie guys on a "lads" holiday. Had an awesome time though, we paid extra to get the wristband thing (can't remember its name) think it was run by an affiliate of thomas cook/thompson (again can't remember) it basically got you in on all the bar crawls, few free drinks, and straight entry into all the clubs, if they offer one of these deals, i would say definately go for it!
Went to a foam/water party in BCM when i went,got like 5 free drinks with the wristband, and a free gift (which was a crappy bag and a couple of shirts) needless to say it was quite messy, BCM is a nice club, albeit a little overrated,but i did go near the end of clubbing season though.
I also don't agree with the sewage comment earlier in this thread, i actually found it to be very clean, actually cleaner than England.
Stick in your little group though, don't be a dickhead and you'll be fine, also if it's the Guardia Civil on duty when you go, try and be a bit more wary/sensible around them, as they are military police, and as far as i've been told, they can be a little heavy handed.
Have fun!
PS stay away from the lucky lucky men