OK, so I installed SQl 2008 RC0 yesterday. It was mostly successful. But it was missing the Business Intelligence stuff. I know that there's an issue where you can't upgrade an existing BI install. But I'm running SQL2005 and I was able to install CTP6 with no problems. Unfortunately I don't remember the steps I took to install BI for SQL2008. I did uninstall CTP6 before starting in on RC0.
I've reverted back to CTP6 and I'll try again. This time I'll document the uninstall steps. I obviously missed something.