i've had a lot of hardware that had no XP64 drivers (or bad ones) - creative sound cards, web cameras, TV tuners, printers, that kind of thing.
If you run mainstream hardware from big companies (and no extra peripherals) then you should be ok. That said, vista x64 and 7x64 have a lot better driver support than xp 64 ever did.
1. creative sucks, their supports been utter shit since the sb16 days, it just became more noticeable as time went on.
2. webcams dont get driver updates, the companies tend to view them as desposible devices you should just buy a new one of(bastards)
3. tv tuners, alot dont have "official" x64 drivers, but if you look up the chip and dig around with google a bit, there are drivers for most conextant/rockwell and other common chip based cards, the card makers just dont post them because they want you to buy a new card.
3. printers, if its a ltp/para port printer you can easly get it working, if its USB you can normally get it working at least in a basic fashion using a generic usb print driver, wont have all the features of a full driver, but u can print.
4. scaners, yet another device that companies see as disposable, and just want you to buy a new one, any time a new OS comes out that changes driver models you endup needing a new one 9/10 times.
yeah there are devices that dont have x64 drivers, but enlarge the same devices lack vista drivers, and if you go back in time, alot of devices that worked on 9x or nt4 didnt ever get 2k or xp drivers
Not really MS's fault but the device makers being bastards, my advice if you dont like that crap, dont buy from companies that do it, and email them letting them know why you wont buy their products again.