@ Ben, I was going to start the exact same topic this evening, I'm not sure what is best, but my head sways toward hyphented .co.uk, I have quite a few on notepad with hypens for the .co.uk and the same available in the .org.uk without a hyphen.
Personally, I don't mind hyphens at all, and they don't seem to affect search engine rankings, and possibly even benefits the name in some examples I have read on this forum, think it was in the hyphens topic in the new domainers sub forum.