Well, all installed now.
I had a major problem during first boot up and I found out that it was due to the VIA SATA drivers being buggy so someone made their own, which work fine:
http://www.64bitstuff.com/index.php?download=26 (free registration needed to download).
The files have to be copied to a floppy and then you press F6 during installation of Windows.
I have installed the drivers for my Audigy 2 and the Radeon 9800 Pro with only one problem - apparently an .inf file was missing but they're still installed.
I expect to be updating the drivers whenever new versions are out.
Other interesting stuff I've noticed is that there is a 64-bit version of Explorer as well as 32-bit for plugins which don't work in the 64-bit one.
As a side note I'll mention that both Firefox and Thunderbird installed with no problems, Flash also works in the former.
I tried to install Media Player 10 but it said it was incompatible with this version of Windows - I checked and I already had a 64-bit version installed.
All the SP2 stuff is included from XP 32 and it looks like the task manager shows which programs are running 32-bit code (see screenshot).
I'm happy with it all so far, very stable (it's based on Server 2003, not XP) and the GUI is
extremely fast.