I didn't have any issues installing WinXP w/ this board. However, I have SP2 slipstreamed into my WinXP CD. So... now SP2 downloads during install for me.
As for which ethernet port is faster... I would venture to say the nVidia one is probably faster. It's directly on the MCP where as the other ethernet port uses an off chip solution that connects to the PCI bus.
I could be wrong though. The difference in performance in real life is probably negligble anyways.
At any rate, I use a wireless NIC. So my opinion can't be relied upon.