I can't claim that it worked first time, but after a Bios update, Windows finally recognised the fact that my motherboard had onboard sound and installed drivers for it.
I have installed all the essentials and even managed to install EQ2 and Crysis (the true essentials!).
EQ2 looks a bit better (it's an old game that can only be taken so far) but Crysis is playable (as opposed to a laggy slideshow) and looks gorgeous.
I'll try and work out some screenies.
Oh and the biggest success...
My new slipstreamed install disk for Windows XP.
My install disk is pre-SP1 and needs SATA drivers to be installed from a floppy drive (which the new PC doesn't have).
Using nLite, Nero and a lot of help from Paul Thurrott's excellent website, I made a Windows XP SP2 disk, which included the SATA drivers. Next time I'll try and incorporate all the MoBo drivers and make it unattended as well.