Windows isn't very good at managing files as they come in and go out - fragments are left behind, files are removed that shouldn't be, and in the end you just give up trying to control what's going on.
Belvedere is a simple background application which can watch over your files to make sure that specific rules are applied to them. For example, you can ask Belvedere that all MP3 files larger than 500KB and whose name contains "Blues" is moved directly into the subdirectory "Blues" in the My Music folder. Unfortunately, this doesn't work for metatags - it only reads the names of the files.
Belvedere can be set to run a huge number of other tasks - just about anything you can do with a file in Windows can be assigned a rule in Belvedere. It can also use multiple criteria, such as the length, name, size or date of creation, each with several options. You have to ensure that Belvedere is always running however because if not, none of the rules are applied.
Belevedere is a very basic looking application with a lot of powerful uses. If used right, it could save you a hell of a lot of confusion although it takes some time to set up if you need several rules.