I try to only rate records that I have heard a good number of times so that the rating is accurate and fair although if I really can't listen to it it's not going to score too high.

I only give ratings 4+ to albums I really enjoy over a good period of time and I usually re-rate quite often, doesn't mean an album with 2 1/2 is horrible or anything, simply average. I tend to give 3 1/2 to albums I really enjoy and If I listen more and more it goes up...

Lastfm: http://www.last.fm/user/Grizz/