I've noticed one small oddity in Time Machine. If you try to completely restore your system from a Time Machine backup, it seems as if Time Machine has gone on holiday to California, rather than staying in wet London or cold Zurich: Your backups all have timestamps which are about nine hours prior to the actual local time at which they were saved.
It's not really a problem, but it is a little disconcerting, especially since by the time you're having to do a full system restall, your nerves are probably a little frayed anyhow.
[robg adds: As I'm located in California's time zone, I can't really test this one very easily. If you can confirm, please comment.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071111011728582