Best/worst bar in London?

[RSJ]

I like this topic on the Dublin sister site. A good time of year for it, too. So what are the best/worst drinking dens for the architectural community in London?

Last night I went to the Architecture Foundation in Bury Street, which has been turned into a bar and crash-out zone by Ben Kelly. I bought an excellent Pomegranate Daiquiri for £4.50, which ain't bad for London, and especially St. James...