I've been collecting for quite a while now, and find that whilst it is very helpful to be able to differentiate between relatively small differences at the top end of the scale, it is not important to know whether a bad recording is simply bad or whether it stinks. Only 'completists' will want those recordings, and they won't care too much about the quality anyway.
So, I have graded everything which I regard as being enjoyable to listen to as either A, A+ or A++. I would recommend A++ and A+ recordings to anyone, and A recordings to big fans looking for interesting but not perfect recordings. Anything else falls under B or (if it's really grim) under C:
A++ An outstandingly good recording or personal favourite
A+ An excellent recording; commercial quality or very close
A A good recording (e.g. a top audience recording)
B Still listenable, but for real fans only (most audience recordings)
C Pretty much unlistenable
? Not yet graded
In the main CD lists, the availability of artwork is shown as a single character before the CD title:
+ Artwork is online
* I have the artwork, but I haven't yet scanned it in
- I don't have any artwork. If *you* do, I'd love a copy !!