I'm interested in this as well. I used to use IndieVolume years ago, but it hardly ever worked without crashing, so I always ended up removing it after a couple of days. It seriously worked maybe 10% of the time without crashing applications at best.
I would love to find some kind of volume wrangler for Windows. It's great that Windows 7 now has individual application level volume control. But I still have issues. At any given master volume, a flash thing online will be at least 10x louder than anything else on my computer. Even if I turn up to max the volume control in a music player or video player, it will never be as loud as a flash thing on the web at half volume. I just don't understand how to control volume on Windows. I don't get it.
It would be great to have a program that can anaylze how loud something is after all the processing is finished. Every program has their own individual volume control, but I don't care about that. I just want to know how loud it is at the end of it all...after the combination of program volume, the wave volume, the master volume. Because that is what reaches our ears. I would love to set a program to be like "Whatever you have to do, never go louder than THIS setting.