Sygate Personal Firewall - The easiest I used so far....
DVD Decrypter - Backing up your precious DVD's does not get any easier.
IsoBuster - a highly specialized yet easy to use CD and DVD data recovery tool. Also very easy CD/DVD Image creator.
Someone mentioned Daemon Tools. I would literaly die without this one....
Although I read somewhere that it removes IE, I use it and with no problems - for spyware active sheilding, monitoring and removing -
MS Antispyware
I try and use only freeware as I am broke as an eggshell under an elephant's stiletto. If I come accross any other gems I will post...