I am trying to put a requirement together for a new environment to consist of TeamCity running of Sql Server, a couple of build agents (for now) and an SVN repository. 

There are 6 developers and there will be 5 active solutions partaking in the CI process for now which will obviously grow over time. None of the solutions take >10 minutes to build currently so they are not huge in terms of complexity & loc.

The build projects will themselves need an instance of sql server so the automated tests can run - I assume they should be kept separate from the TeamCity sql instance.

Can anyone suggest a hardware config suitable to run these. Is disk i/o going to be more important than actual CPU power.

Can I run all these on a single multi cpu, raid and virtualisation? 

Should we be running with windows 2008 and hyper-v?

I have always let others deal with server requirements and build but now I have to get my feet dirty. 

Any advice most welcome