As of today there is at least one hotfix available for SQL Server 2008, and it involves Itzik Ben-Gan's reported foreign key validation problem with the new MERGE command.  You can read about the bug here:

http://web.archive.org/web/*/https://connect.microsoft.com/SQL/feedback/ViewFeedback.aspx?FeedbackID=357419

And about the fixes/workarounds in KB #:

http://support.microsoft.com/kb/956718

More importantly, I have received confirmation that for SQL Server 2008, the SQL Server sustained engineering team will continue with the same tradition of releasing regularly scheduled cumulative updates for the foreseeable lifetime of the product.  I've talked about it before, but you can read about this process here (even though it currently doesn't explicitly state that it applies to SQL Server 2008):

http://blogs.msdn.com/sqlreleaseservices/archive/2008/04/15/cumulative-update-7-for-sql-server-2005-service-pack-2-2.aspx

And here:

http://support.microsoft.com/kb/935897

In this case, you should expect the first cumulative update for SQL Server 2008 to be available sometime in September (watch KB #956717).  I'm hoping to see a nice big list of fixes when the update is published, but to be honest, I have a narrow short list that I would be extremely happy about.  🙂