a few here, which vary in quality
egg - midsized - seedy atmosphere tho - personally hate it although loft is ok
se1 club
http://www.seone-london.com/intro.html
pacha (each to their own..)
cargo - (some good house nights - generally live/soul/broken/jazz - never for prog fans!)
east village (consistently best lineups around, if you like the deep, druggy stuff - location means occasional struggle to keep the ben sherman/beer boys out tho)
koko (old camden palace - if you're desperate)
dex (amazing venue - rooftop spa included)
hub - near liverpool st - on 2 floors, still in embryonic form, think it's leased to nus - potentially very good
plan b brixton - new basement gives it a more raw flavour - upstairs, getting high st crowd in avoid - classic house lineups, no messing about
333 - old street - dark, dingy, one for the alternative/electro crew - painfully cool... Do your homework first...