You use what works with you.
One thing though, I do wonder about all the posts I see here where they use registry cleaners. I never do. My Windows registry does not need cleaning, defragging, or anything else, and I am much more comfortable with not interfering with it. We see too many horror stories of the damage that is caused after a registry cleaner has cleaned out some crucial entry or key, and the user cannot get back in to the system again.
Ohh, and whilst I'm here, 
I prefer small. Small is beautiful. Small utilities, quick, easy, no bells and whistles, they just do the job. Then these utilities add more 'useful' components, and before you know it, they get bloated, resource hogging, and try to take over. I usually move on then.
Mark
Apps like Glary Utilities, TweakNow Power Pack, Spybot, Ad-Aware, etc etc etc are able to perform multiple tasks. Full, large programs are devoted to taking aim at single tasks instead, which of course begs the obvious question---why waste time with a registry cleaner or spyware remover when you can do it all at once? After choosing your AV/firewall combination are we really optimized by downloading a single handful of programs to ice every need? Shoot, if you were to believe the newest Spybot and Ad-Aware crowd you won't even need a firewall to begin with.
Obviously that isn't true but where is this imaginary line? I love Glary, for example, to clean the registry and free up space, but in no way will it keep Malwarebytes off my system because of the spyware remover.
My ultimate question is blunt: Do I compliment Avira and Zone Alarm with Glary, Malwarebytes and Smart Defrag to cover all bases or will it make a noticeable difference to pick up one program for each task? This includes the best of the best multi-purpose programs vs THE best single-task utilities. Everybody has the space for the latter but everybody +1 would rather take care of it short and sweet. Freeware and recommendations encouraged, please.
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic