My problem is that I'm using Vista 32-bit and testing Windows 7 beta 64-bit. No upgrade path there, so I've got a dual boot option.
The problem is, I have two partitions on a single drive, and I made the mistake of installing Windows 7 on my second partition (that already had some stuff on it) instead of on a separate drive. Now I have to move my data to a second physical hard drive, uninstall Windows 7 beta, move the data back to the partition, then reinstall the RC to another drive. Ok so I could keep the data on the separate drive and install the RC to the secondary partition to save a step, but it's still quite a bit of trouble.
Then again, it's my own stupidity that got me in this situation in the first place.