I've already tried 2x1 GB... Result = constant BSODs. P4C800 (and P4P800 for that matter) is picky about ram, even though the manual mentions that it does support up to 4 gigs of ram.
Besides, even if I somehow find those 'proper' 2x1 GB sticks... I'll still be stuck with my P4 2.6c because I won't be able to OC.