ItoWorld.com has produced a really neat visualization of 2008's OpenStreetMap edits. It starts zoomed in on Ipswich, which is not far from my former home of Colchester, and I was quite pleased to see the little flash of Colchester as it zooms out... that's (partially) me! You wouldn't spot it if you didn't know exactly what to look for, but whatever.
More interesting on the global scale is just how much editing went on last year, not only in the UK but all over the world. It's great to see OpenStreetMap taking off, though I'm still sceptical whether it can really ever have any use beyond getting CC-licenced maps to go on a website's "How To Find Us" page, since you can't rely on it for any place you don't know. (Having said that, though, there are of course parts of the world where maps are not so readily available, and I do hope OpenStreetMap can go some way to addressing that problem.)
(FWIW, Colchester is still incomplete &mdash there are a few folks still working on it, but there are still large chunks of it not mapped — but I believe neighbouring town Wivenhoe (which is where I actually lived) has all of the important streetmap-level details.)