Rating system:
5 stars - Would not change a note
Ex. Who's Next, Abbey Road
4.5 stars - Wouldn't remove any song, but might tweak one or two
Ex. Aeroplane Over the Sea
4.0 stars - Most of my albums - excellent albums, often listened to. Maybe one or two songs I could do without
Ex. Smashing Pumpkins - Siamese Dream
3.5 stars - Good, but flawed album - lke a C+ or B- grade, some filler or some lameness
Ex. Yes - Tormato
3.0 stars - OK album, but a decent amount of filler
Ex. Anderson, Bruford, Wakeman, Howe (that might be a tad high come to think of it)

Its rare for me to hold onto anything under 3 stars. To me a 2.5 stars is the equivlent to a C- on a test. I dont hang onto those and rarely buy or download one, because I usually know what I'm getting.

Here's a couple 2.5s that I have - Eminem - Encore, Neil Young - Everybody's Rocking.
The only albums I have rated under 2.5 are a Fixx album and a She Wants Revenge album. Both of which I basically heard by accident.