– Application Experience
– Computer Browser (If your PC does not connect to any network)
– Desktop Window Manager Session Manager (If you don’t want the aero effects)
– Diagnostic Policy Service
– Distributed Link Tracking Client
– IP Helper
– Offline Files
– Portable Device Enumerator Service
– Print Spooler (If you do not use Printer)
– Protected Storage
– Remote Registry (You can safely disable it for more Security)
– Secondary Logon
– Security Center
– Server (If your computer do not connect with any network)
– Tablet PC Input Service
– TCP/IP NetBIOS Helper
– Themes ( If you want any aero and good visual appearence (classic theme will be applied))
– Windows Error Reporting Service
– Windows Media Center Service Launcher
– Windows Search (If you rarely use Windows Search feature )
– Windows Time (If you do not want to synchronize system time with internet time automatically)

ref: http://www.computingunleashed.com/list-of-services-in-windows-7-that-can.html