Another strategy avoids swapping drives. I currently have 5 partitions on the boot 1.5Tb drive(3 primary); 30Gb windows (why give space to a fossil?; I'm trying to debug why my TV tuner card won't work), 2 by 25Gb ext3 partitions, and an extended partition containing both swap and a huge encrypted partition for all data.
This makes it very easy to play with new RC's; keep the working system on 1 ext3 partition, use the other for the new system. When the new system is debugged, use it as the main and overwrite the other for RC's. Only takes adding a couple of lines to lilo.conf on the newly installed system to access the old partition. Just have to remember to have run lilo on the old system with install pointed at the partion itself, so there is something there for the 'new' lilo to boot.
I'd make the 25Gb ext3's bigger when doing it again; getting a bit tight....