OpenBSD 3.9 installed like a dream. There's a nice CD ISO for booting. The apm work done by the OpenBSD developers has really show since it's not necessary to disable apm in the kernel config. I decided to try something a little different and installed OpenBSD using QEMU with an LVM logical volume. With the correct permissions it seemed to just work. I don't know if it'll be any use. Possibly using LVM with the Device Mapper offers better preformance.
Installing Windows 2000 into a QEMU VM I opted for using 256M of RAM which seemed to work better than the default of 128M.
Of course you need to create a disk image. You could use -cdrom win2k.iso if you wished rather than -cdrom /dev/cdrom. But that would probably break copyright rules.
To install Windows 2000 it took about an hour to install, but that was using kqemu the kernel module. Without the kernel module it took about 3 hours with version 0.7.