As I was heading up to Covent Garden last night, I realised that one of the best views of London from the river can be had from the north side of Waterloo Bridge. To the east you can see St. Pauls, the Nat-West tower, the Gherkin, Canary Wharf and the OXO Tower. To the west you can see the South Bank Centre, the London Eye, Westminster and Charing Cross. It's lovely on a summer's evening.
The view east, with the Embankment to the left.
The view west.
(Sorry about the rather poor photographs though, I'm afraid my phone isn't really up to this kind of panoramic photography...)