Well, I'm a bit younger than most of you, but lately it seems that when you buy a cd, you're buying it for one or two songs at most, and the rest of them are awful.
So, using that as a benchmark, I'd say any of the first three albums by Eminem rank on the top CDs list simply by their virtue of having, at most, one or two bad songs, while the rest are very good.
Dr. Dre's 2001 is a great CD for the same reason.
Of course, this is assuming you like rap/hip hop.