Hmm...I've never had issues with my nforce3 Ultra or nForce4 Ultra boards (MSI K8N Neo 2 Platinum and Neo 4 Platinum) nor with my nForce 400 Ultra (MSI K2N Delta2 ILSR). Then again, I haven't had a scanner hooked to it; so far, I've had a Treo 650, QuickCam Pro, Logitech MX-1000, and my Fuji FinePix S5000 digital camera.
On another note, I'll probably be building a high-end system for my sis/brother-in-law soon. Hope to go with an Intel BadAxe board and a Core 2 Duo. Hox, what board did the Intel deal include again?