Some things to adjust when the svchost service becomes large
From a command prompt:
ipconfig /flushdns
Go to Services
Stop and switch to "manual" start
DHCP client (you will need this for ActiveSync or DHCP)
DNS client
Help and Support
Indexing Service
IPSEC Services
Lightscribe Service
Messenger
Net Logon
NetMeeting
Remote Access - multiple of these
Remote Desktop
Remote Procedure
Remote Registry