Die Evolution Die
This may well be en_GB sucking really badly (until recently in Ubuntu it didn't have 24-hour time either), but this is really bad form for a birthday field:
Someone will be first up against the wall, mark my words. A bug is filed, fingers crossed it gets fixed soon.
Update: Richard "bork bork" Hult, running in sv_SE, has a four digit year field. en_GB sucks.
NP: Gonzo Jazz, Margin of Safety
While something like liferea shows the date as YYYY-MM-DD, those date boxes in Evolution 2.4.2.1 still show it in MM/DD/YYYY format.
It sucks that there's aparently no user-level nome tool for overriding locale display prefs (via the clock applet prefs for example).