Many folks are interested in guidance on hardware.  In the Team Foundation forum, Brian Harry, Product Unit Manager of Team Foundation, posted the latest preliminary hardware requirements.

If you are going with a single processor box (or if you want to maximize performance), I would recommend changing the warehouse update interval to reduce the load on the server.

Configuration

Tiers

CPU

HD

Memory

One server, less than 20 users.

Application and data tier server

single processor, 2.2 GHz

8 GB

1 GB

One server; 20 to 100 users.

Application and data tier server

dual processors, 2.2 GHz

30 GB

2 GB

Two servers; 100 to 250 users.

 

Application tier server

single processor, 2.2 GHz

20 GB

1 GB

Data tier server

dual processors, 2.2 GHz

80 GB

2 GB

Two servers; 250 to 500 users.

 

Application tier server

dual processors, 2.2 GHz

40 GB

2 GB

Data tier server

quadruple processors, 2.2 GHz

150 GB

4 GB