Throughout the Team Foundation Installation Guide, you'll see references to the following user accounts: TFSSetup, TFSReports, TFSService, and TFSProxy. I just want to dispel the myth that there's some correlation between using these literal names and successfully installing Team Foundation Server. As noted in the Team Foundation Installation Guide help topic, User Accounts Required for Team Foundation Server Setup:
This installation guide refers to these accounts by a placeholder name as noted in the table. If you want to use different user logon names, or if you have existing accounts you can use, make sure that you substitute the correct name as appropriate during setup.
In the early releases of the Installation Guide, I needed some way to distinguish the different accounts that you need to install Team Foundation Server. For a simple notation, I just gave them the descriptive names that they now have. You DO NOT need to use those specific names to install Team Foundation Server.
If you are installing Team Foundation Server Workgroup Edition, setup adds the setup account to the Team Foundation Licensed Users group. For this reason, I would suggest installing Team Foundation Server using one of the user accounts that will use Team Foundation Server.