I'm just putting this in my blog to help other people who search on this.
Most Debian-based installers don't work. They get hung up on the Grub install, and it throws a Grub error. Just continue and install Lilo instead and forget Grub, since it won't work until they fix something (spent 2 days on this!).
To do anything more, you have to build a new kernel. You can use 'defconfig', but the killer here is the fussy drivers for the sata drives. You need the 'experimental' piix drivers, and kill the standard piix. As well, you need to look in the gigabyte network drivers, and pick r8169.
The new kernel should work and you can install the Nvidia drivers from the Nvidia site. This gets everything working, but my son wants the spiffy 3-d compiz interface, which is proving to be a problem.
ps. Got compiz working! Man, is that a neat 3-d desktop, with rotating cubes, bouncy things, weird effects and everything!