Fine.
> I want to run XP so I wipe my hard drive and install XP Home (or Pro).
NO!
Leave Vista on the new machine. Just don't do anything with it except install VMware, and run XP in the VM. No need to ever see Vista except when you boot the machine cold. And the pre-packaged drivers in Vista for your Vista-only hardware do the work for you underneath Vmware. XP never has to see them.
> > Am I now screwed because I have no printer driver for that laptop hardware? In other words, is the printer driver machine (hardware) specific or operating system specific or both?
Printer drivers are sometimes OS-specific, but are rarely (in my experience never) host machine hardware-specific.
You can attach printers or other peripherals to the Vista host machine, and "connect" them into the XP VM by choice. Or if the printer is Vista-only, install it for Vista and "share" it over the (totally internal) network to the XP VM as a Windows shared printer with a more generic (XP-compatible) interface.
Except that by doing so, you just lost a good 20-25% of the speed over native XP, since Vista adds that much overhead.
So all the bad things about Vista (excessive shut down times, file transfer problems, clunky slow operation, the need for excessive amounts of RAM, etc.) go away? Just like that?