I don't remember Crystal Palace as being a U-turn before the current bus station - buses from the north end of Crystal Palace Parade were supposed to use the roundabout at the top of Anerley Hill, and buses from the south had an off road turning circle on the east side of Crystal Palace Parade. I think it might just have been possible to do a u-turn with an RT but not sure anything longer would have made it.
(Incidentally, Crystal Palace had an odd feature for many decades in that all bus routes serving it terminated there, with no through routes.)
Honor Oak is now the southern terminus of the 63 which does the Kings Cross - Honor Oak bit, the 363 does the Crystal Palace end, running as far north as the Elephant (I think the 63 was formally run 'in sections' like that some of the time) with only the night service running through. (Incidentally, the extension south of Honor Oak was one of very few services on LT buses that replaced a railway line (Crystal Palace High Level) on closure.)
There is an arrangement similar to the Honor Oak terminus with a nearside southbound 'bus gate' allowing a traffic signal assisted u-turn at the junction of Waterloo Road / Pearman Street, just south of the 'Old Vic' - think it's used by the 4 and 26 terminating from the north, although TfL may have re-shuffled things since I noticed it. (There are some quite imaginitive bus stands around Waterloo, including one in the middle of Baylis Road for the 76s)
I can't immediately think of any others in London. The Wokingham Road terminus in Reading is still used by the frequent cross town 17 service, although it's not used by trolleybuses any more (photo at
http://www.geograph.org.uk/photo/561940 ) - I am told that there is a trick in getting the nearside door pillar exactly level with a 'no loading' marking on the kerb, and starting steering at that exact point, to getting one of Reading's long wheelbase double deckers round in one go...
(Edited to add - I did try to recreate that photo with a 17 a few months ago, and the driver didn't manage the turn very well...)