I've now made a %type% tag where I have information about what kind of collection it is, if it's a studio album, live album, single, ep, bootleg, mixed artist compilation, soundtrack and so on. I've put it in the sorting and it works beautifully.
I've also made tags for debuts (yes (TRUE)/no (missing)) and bonus tracks that I use in grouping.
So far it's all woking out great and I'm loving it
But, I got a question - how (or where) did you get that nifty stuff with the flags, information and so on on the right hand side of your foobar?