So here's my basic rating scale:

0-1.5 stars: probably not even worth rating, certainly not worth listening to, or owning, unless it's for shclock factor.

2-2.5 stars: maybe there's one good song, but that's about all.

3-3.5 stars: fairly memorable as a whole and/or a good album for it's time, but perhaps a bit dated these days. The kind of album that you put on only for specific occasions.

4 stars: this is a damn good album, and one that stands the test of time. These are the albums I like a lot, but have to be in the right mood to want to listen to. (There may also be some rather sentimental favorites that get this rating).

4.5 stars: Nothing sentimental about it. If an album makes it to this level it's just great through and through. It's not usually hard to get me to listen to these records.

5.0 stars: The cream of the crop. The flawless albums. The ones I can, will, and do listen to at any time. My all-time faves.

that's it, subjective as it may be, that's my rating system.