Bold = I sometimes say, italic = I have said, plain = would never say (as a swear word)
Wanker (I don't think of this as particularly offensive)
Shag (would probably use mainly when imitating another person's speech)
Twat (trying not to use)
Slag (would only use in imitation 'You slaag')
Jew (Haven't heard used as an insult since the 1970s. However, I usually say 'a jewish person' when I'm talking about religion. This may show that insulting use hasn't completely vanished?)
On Language log there is a discussion of the use of 'spastic' or 'spazz' as an insult. In the UK it is completely unacceptable. There was outrage when Tiger Woods used it to describe a poor golf performance ('As soon as I got on the green I was a spaz'). Language Log explains that in the US the word has become so dissociated from disabled people that it isn't seen as offensive. I can only conclude that true, because Tiger Woods seems to be a controlled and media-savvy person. He did apologise for his words. No British sportsman would use that term in public.