You can turn off certain services.
I don;t have a list compiled, but I disabled these entries. Please do not go by my guidelines as this pertains to my personal desktop PC.
Internet Connection Sharing
Parental Controls
Smart Card
Smart Card Removal Policy
Tablet PC Input
Windows defender
Windows Firewall (Have my own)
Media Center Options can be disabled if your not using them (such as the Extender Service)
Windows Media Player Network Sharing Service
When you install 3rd party software, go to Start > Run, and type msconfig, click the Startup tab to see what's loading with Windows. All you need is Anti-virus, spyware detection or personal firewall if you gave one.
You can also remove some of Windows 7 features, including...