Go to the OXO building. They have an observation area on the top floor overlooking the river which you can photograph from.
Steve.
And a really good gallery. Didn't know about the observation platform.
We usually get down to Charring Cross/Embankment tube station, cross the footbridge and walk the south bank.
You've got festival hall and the national theatre with Graffiti underneath and skateboarders, plus the book market, joggers etc.
Then further along you have the Tate Modern, Millenium bridge with St Pauls on the opposite side, shakesperes globe theatre, the buskers under southwark bridge and the golden hind.
Then you get London bridge, Southwark catedral and Borough market, before the walk back along past HMS Belfast, the GLC glass building and Tower bridge, with the tower of london in the background.
Plenty of places to stop, eat, drink, photograph.
If you're feeling energetic you can cross Tower bridge, walk back down the others side of the river with St pauls, Fleet street, the Temple area with all the old baristers courts, Royal courts, then ST Clement Danes church - the church of the RAF with the statue of Bomber Harris outside.
My fav bit of london to walk in.