Speed up Windows Vista

Go to Control Panel and click on Programs and Features

Click on Turn Windows features on or off

After this will appear windows feature window. Here you can turn on or off every windows feature. Turn off those you don´t need. Below is list of features that you should turn off.
Games (If you love vista games (Solitaire,Minesweeper and etc.), don´t touch this)
Indexing Service
Internet Information Services (support for web and FTP servers, necessary if you hosting websites on computer)
Microsoft .NET Framework 3.0 (this is for .NET 3.0 components, necessary if you are programmer )
Microsoft Message Queue (MSMQ) Server (technology enables applications running at different times to communicate across heterogeneous networks and systems that may be temporarily offline. Simple said ,useful only for programmers. Learn more about MSMQ on this link )
Print Services (Necessary if you are using internet printers)
Removable Storage Management
RIP Listener
Simple TCPIP services
SNMP feature
Telnet Client
Telnet Server
TFTP Client
Windows DFS Replication Service
Windows Meeting Space