I am running all my gameserver services (L4D, CoD, TS3) with the local service account. A useful guide by Microsoft "The Services and Service Accounts Security Planning Guide" can be found as PDF here which has the main goal to help administrators reduce the effect of a compromised service on a host operating system.
http://www.microsoft.com/downloads/details.aspx?FamilyId=F4069A30-01D7-43E8-8B30-3799DB2D9C2F&displaylang=en The guide is for Windows Server 2003 and XP but it does also fit for Windows Server 2008. *Excerpt:* A least-privilege hierarchy should use accounts in the following order: 1. *Local Service* This account is similar to Local System, although it has minimum privileges on the local computer. Services that log on as Local Service access network resources using a null session with anonymous credentials. The account's privileges must be limited to only those that are required for the successful operation of the service. 2. *Network Service* This account is similar to Local System, although it has minimum privileges on the local computer. Services that log on as Network Service access network resources using the credentials of the computer account (where the computer is referenced as <domain_name\computer_name>$). The account's privileges must be limited to only those that are required for the successful operation of the service. 3. *Unique user account* A service should run as a unique user account only if it is impractical to run it as Local Service or Network Service. You should use a unique local user account to run services that only require privileges on the local computer, such as IIS and SQL Server. ... 4. ... _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlds

