Martin:
Metro - big club, lots of girls, but most under 21 (not necessarily a bad thing). The ultra young girls tend to be more enthusiastic about meeting foreign guys than the older ones (they haven't been burned by broken promises yet....).
Marstall - lots of foreign guys. Sometimes a working girl or two. Its fairly small - more like a bar, with a small dance floor. Very hit or miss trying to meet girls, as its small, but the ones who do go know it is a foreign business man's hangout, so they are likely there to meet you...
Red Lion - a large bar. A good place to try and meet local girls, but most sitting at table with Reviewiends - tougher atmosphere to meet people. There is a dance floor, but not always happening - place more popular as a kind of beer pub type atmosphere.
Magrib - decent sized club, bar, working sp-girls, local regular girls, foreign guys. A good mix of what you'd be looking for, but pricey cover to match (like $20, if I remember correctly).
Strip Club - there is strip club right buy Nevsky/Fontanka - never been there - guarantee its expensive, don't know about take-out action, but would be pricey. Magrib is a better option. I'd avoid, unless you have serious money to blow (like, $500+ for the club and girl, one evening, just my prediction). If you don't mind blowing serious money, the very hottest girls (modelesque) would likely be found at this place (you won't find model quality at any of the salons).