A nice feature has been introduced with MOSS  2010: The farm configuration wieeard, this tools configure quickly your farm, web application and site collections, in our case we discuss about the service account and the rights granting by this wizzard into the system....

Go to your Central Admin page and read the following article.

After clicking on the Configuration Farm Wizzard, the system ask you for a service account, please create this account first in the Active Directory with no privilege only Domain Users.

Choose your services...

Note: In your example, we skip the site collection collection....

Ok now we have services configured, we look on our server the privileges granted by this setup for this account:

This account is member of: IIS_IUSRS, WSS_WPG, Performance Monitor Users.
This account have the following privileges: Adjust a Memory Quotas for a process, Logon as service, Replace a level token.