Here's my daughter's story. They had a family computer that everyone used. Then she wanted a laptop. They set up a wireless home network. The laptop she bought was a Toshiba with Vista. The family computer had XP Professional. After a year of trying to make the Toshiba talk to her HP printer, she never succeeded, either through the network or directly connected. Toshiba and MS both told her the only solution was to buy a new printer. (They had just bought it for like $400 - it's a high end machine, and there was no way they were going to replace it.)
So, we took Vista off the Toshiba and loaded XP onto it. Well, everything was fine, except for the fact that the sound card wouldn't work. Apparently, the sound card was "Vista only". But now the printer worked.
And ultimately, after frustration with the sound card and a few other minor problems, they took the Toshiba, tossed it in the trash, and bought a new Dell Inspiron with XP. It worked out of the box, even wirelessly with the printer.
I, too, just bought a new Dell Inspiron with XP. I'm not EVER going to Vista. I might go to 7, we'll see.