There's very little hardware that won't accommodate a 64-bit operating system these days. Moving to Windows 7 from XP was a huge improvement in many things. As such, I'm pretty uninterested in Windows 8 at this time. I have four or five W7-64 machines around the house....we're staying put.
Now, for someone still on XP......perhaps. But, AVB makes a good point - there will be bugs 'o plenty found once the OS is in the hands of the consumer. It may be worth waiting but if you have a time limit on the W8 upgrade, that may force your play. If i were still on XP, I would probably be lots more interested in W8.
You know, it seems like every other MS OS is a dog. I rode XP through Vista into W7...which rocks. I think I'll hang with W7 until W8's replacement shows up in two years.