I hear 64 bit systems are great for home use / gamers. Almost every device has a driver for it now. But from a business standpoint 64 bit is nowhere near what it needs to be and that is the fault of the programming for business applications like cisco vpn, honda IN (for honda dealers), and almost all medical applications.
Had a sales lead for a shop put in vista 64 bit on all the machines and shut down the whole sales department for a week and a half because of application compatibility, only to reimage back to xp. Those apps are still not compatible with 64 bit.