I take an entirely different view to the complete problem.
It seems like people do worry about the idea of "Bloat" on their drives and what impact it has??
My approach is totally different, I could care less about how efficient bytes are used. I dedicate the Drive C to only the OS and its associated files. At present on the system I am typing on, the Drive C is a 40G drive, using something like a wopping 4G's, some of that is a back up file that is also maintained on that drive. Duh, a copy on the same drive.
No partitions, no fancy anything. I only bought a 40G because it was about the same price as a 20G, could have gotten away with a 10G and been swimming in spare capacity.
Part of it is how you attempt to tackle various problems. I don't use Drive C for routine purposes. Never download to it, never use it as a work area, never do anything that involves a lot of read / write / erase / rework type moving data about. Basically set up the system, occasionally add or delete a program.
Everything else happens in a "Work Area" on a Zip Drive or on a physical hard drive loaded as a data drive. These data drives are swappable via a removable rack / tray system. This idea of recycle bin never comes into play because a Zip Drive deletes are not saved or related to the recycle bin. All my bad ideas, simply go down the drain about like operating from a floppy. Very little impact. Also all downloads must go to a ZIP. Almost nothing of a "Raw Unprocessed Nature" goes to any hard drive.
Therefore defragging isn't a big concern, rarely needed, security is greatly enhanced, back ups become far more easy to do.
Basically my approach always questions "Exactly how do I keep the OS in peak condition"???? Plus how do I keep it totally secure??? One big goal is never, never, never have to ever reload the OS. In coming on ten years, I have met that goal.
So, my basic argument "Bloat" is not the concern if you design the system correctly in terms of hardware. Slowly but surely I am proving this out to myself. I use Win98Se, Win2000 and Win XP Pro in a swappable system where OS's can share two separate hardware systems. I prefer to surf with Win98SE.
Always in the market for new ideas or new programs that sort of support my goals. Started using CCleaner, like the results. Lately have gotten more into this idea of the "Tracks One is Leaving" in various files. I went back and investigated how to be editing or managing the Registry. Sort of now convincing myself, it is far more about how the Registry is organized, defragged or compacted than its size or bloat.
Guess to this stage I am happy, would like to find a program that can "Erase tracks in the data area of the Registry, I can do it manually. Always that trade off between your desires and the next screw up.
If there is any magic touch stone to any of it. You can have too many methods of back up and hopeful one of them will work on restore.
So I don't think the size of the bloat is the problem but more how the OS is organized to work around it. My fear is always mindless programs to cure "Bloat" screw up and the back ups don't work.
Plus I rarely can ever see a positive result on decreasing "Bloat" size to increased OS performance directly, assuming nothing else changed. Think I am saying size doesn't matter as well as it is well organized.
With brings us to the problem of what programs to use for getting organized. Think I am say, first the Registry optimizing programs are the ones to look at, defrag if you are old school, mega one hard drive user, a World impossible to balance out.