I agree with not using any at all. These tools cause more trouble than they fix. Empty your browsers caches manually and keep a decent filing system for your files and you will be fine. Use Msconfig to remove startup apps, if you aren't sure of what it is, don't turn it off.
Tune up utilities actually tend to be bloated and large pieces of software, and run at startup, actually slowing you down more...
If you want speed for your OS, get an SSD. I bought a 120GB SSD for my OS and main applications, never looked back.