I had a nforce4 mobo until a month or so ago, and it was just never quite entirely right on either PATA or SATA. Fought with it for two years, with random lockups in both XP and Vista that only occurred just enough to be annoying, and would usually release to normal operation again after a minute or so. Dunno if it wasn't the right drivers or just fundamentally fubared somehow. It also ate three hdd, tho I can't prove for sure that was the mobos fault --even tho that is by far the most hdd failures I've had in a two year period.
Anyway, my new X38 chipset mobo has been flawless so far, so yay. Good luck on your issues.