Not really done much haggling in the UK, but in other countries I've done it loads. Done it a few times when drunk and ended up buying things I didn't really want, just because they came down to my starting price
My personal best was a giant fan with a picture on it, about 1.5 meters across. Starting price was 130RMB and got the lady down to 10 RMB for it. Paintings were also good for haggling.
http://i55.photobucket.com/albums/g137/robeccleston/P1020733.jpg
I got this for 50RMB (~£5) down from a starting price of 380.... Then went to a pottery factory in Beijing and saw the same thing with a marked price of 2880