Good XP/Vista Optimizers?

I’ve been working on computers for a while now, just small stuff, anti virus, tweaks, general maintenance for friends and people i meet. Through this, i’ve started a small list of programs and reg tweaks i like, but i know there is a lot more. I’m just wondering if anyone has any suggestions to what they use or like. I put a quick list of things i use together, they include the following:

AVG anti virus
Spybot S&D
Regscrub
Defraggler
Autostart
TuneXP
TweakUI
Revo Uninstaller
Sys Properties>Performance>Visual Effects
Comodo Firewall
HiJackThis free
The built in "disk clean" option under My Computer
Random Group of Registry tweaks I kinda put together

Any advice is appreciated. They can be programs or reg tweaks. I prefer freeware, but i am willing to pay if they are really good.

Thanks

I scan with both AVG & Malware and they both say they have cleaned,healed and moved to virus vault this infection but it keeps coming back. It has disabled my MIscrosoft security center for any updates and its seems to be in the registry. ANY HELP WOULD BE GREATLY APPREICATED–GOING BONKERS!!!!!

I want to repartition & reformat harddisk and make a clean installation of ‘XP pro sp2’

My computer is really messed up, and won’t stop freezing out of nowhere! With research, I found out that I have to clean out my registry and i downloaded a bunch of scans like: Regcure
However, the scans spot my problems, but I can’t fix them because I have to pay. I tried looking for free registry cleaners online, but all the ‘free’ ones are just scans x/ theyy don’t fix the problem without me having to put a serial keyD:
http://www.regace.com/?hop=richpeck17&TID=FRF
^ like that for instance.
Are there any COMPLETELY FREE registry cleaners?