Ok, as Colin says a weeky or even daily run with ccleaner helps a bit.
A weekly scan with spybot search and destroy will help also, even if it finds nothing as it clears cache anyway.
Also "Start>(type) msconfig> run that> check "selective startup".
Now click the "startup" tab and uncheck the lot baring your antivirus.
Now click on the "services" tab and sort by manufacturer.
Now uncheck ones you do not want to start up that are non microsoft, spybot search and destroy for example or apple stuff i,.e bonjour service.
These can easily be started by services in task manager so it will not hinder or adversely affect your experience.
You can also turn a loud of microsoft stuff of like "superfetch" and "volume shadow copy".
Error reporting service, remote registry, turn them off.
Defrag your os partition, i suggest you use perfectdisk.
If you use firefox use fasterfox lite addon.
Use a low resource hogging antivirus, do not have multiple antivirus running at once either.
If i can think of more tips i will add them, and yes i know what superfetch does but in newer systems it is not really needed.
Response times are fine without having stuff preloaded into ram and boot times are about 5sec longer if that.
If you have ssd then you defo have no need for superfetch.