Am I using all the necessary tools to keep my installation in good condition?

[willhub]

As above.

I use:

Avast Antivirus - as I understand this is one of the best AV's?
CCleaner
MyDefrag - is there any defrag program better?

I make sure all the apps not really needed at startup are disabled in MSConfig.

Anything else good for maintenance?

Cheers.