I personally think the opposite than DrewUK (sorry
). Pacha is generally full of nobs and many posh people, the most gorgeous ladies and cutest guys, but too posh and not to party hard IMHO. There are even many places restricted for VIPs only.
Amnesia is different each night depending on the party you're going to. If you like house La Troya is your party. If you like trance it's Cream, and if you like techno, it's Cocoon.
However I must say that both Cream and Cocoon are populated by very young crowds in the inner room while the terrace doesn't attract crowds despite being better for me.
As for Space, We Love Sundays and Matinee are a must IMO.