SQL 2005 on Server 2008

We are building a new server which is currently 2003 data center with SQL 2005. The app team and DB team would like to keep everything the same. I would like to use 2008 R2 as the OS. This wil be an active/passive cluster.

Which is the better option:

1) install SQL 2005 on 2008 R2 and address known issues with SQL 2005 on server 2008 R2.

2) install SQL 2005 on 2003 data center, keep everything the same, no new issues or workarounds.

Thanks,

Paul