I do wish the desktop world would just move wholesale to 64 bit, but do note that Ubuntu still marks the 32 bit install the "recommended" one, so I would guess there must be some sort of problems that are lingering in the 64 bit versions. Maybe just flash support or something like that?
I don't think there are problems with 64 bit versions, but many computers are still 32 bits. The PC I use right now is 32 bits and I don't feel the urge to buy a new one. So I suppose 32 bit machines will stay around for another decade or so.
