I'll be honest I have mixed feelings about this. Bitcoin is an open source project. I like TradeHill, but I'm no more happy about trade hill controlling bitcoin.com then I would be if RedHad got Linux.com or Apple got w3c.org.
Those are pretty crap examples. Bitcoin already uses bitcoin.org. Though not unilateral these days, the .com TLD was clearly meant for commercial enterprise, and is overwhelmingly used to that end.
I don't think there will be much confusion over it. I don't hear anyone complaining about the domain squatter that has bitcointalk.com, after all...
-jp