We've tested with both, but if you're trying to keep things simpler, I'd use the "regular" (non-R2) version of Windows 2003. It's not that R2 won't work, but the pre-R2 version has gotten more testing (naturally, it was what we had available during our development).
Now, since there are some new features in R2, if any of those are particularly useful for you, then you should feel comfortable going with R2 with TFS on top of it. But if it's the same either way to you, I'd recommend just sticking with 2003 for now.
Team Foundation Server - http://blogs.msdn.com/jmanning/ |