I suspect my response to this is the same as my response to the question: Is there a perfect film? The answer is no, but if there were such a thing as a perfect film/album, it might look like (insert choice here).

Regarding the albums listed here, there are some greats, no question. My U2 choice would be Achtung Baby over The Joshua Tree (great though it is). And yes to Rumours and Thriller in particular. My choice for "perfect" album? Actually, by Pet Shop Boys, though it isn't perfect, because I much prefer the single version of Heart. :)