hrm....
not counting the backwards compatability things?...
call of duty 2 as far as i know, just to fix some XBL lag issues.
and a few patches for the interface itself.
Well, I should say, including content+bug fixing patches. I'm just wondering if the addition of an HD in particular has led to a tendency to release-then-patch as seems to be with PC games.
I did do a cursory check myself; Oblivion reportedly has a patch, Prey will have a bug-fix patch, Saints Row is to be patched (seeing that is what sparked my curiousity, as it seems to be regularly that patch news crops up for the 360 nowadays), The Outfit had a patch, Hitman was patched, DOA4 had one, and BF2:MC was patched. I think Dead Rising might be due a patch, I don't think PGR3, Kameo or PDZ had one (AFAIK).
(NB: including minor patches like, for example, the BF2 one was to fix headset problems)