I've just come across the perfrect CS map: It is (wait for it... wait for it...) IIMA Campus! Seriously no kidding - the layout of the place, the brickey red feel, short buildings. Archways, big round holes, seedy spots to snipe from.
Windows overlooking courtyards, quick confusing exits to dart in and out of, curving stairwells. Brilliant I say.
And to top it off is the dusty, grimy atmosphere. It feels like de_dust with a slight tinge of de_aztec.