Other two suggestions:
Confessions on a Dance Floor (Madonna): Score very well in Musical Impact and Popularity, with ten million copies sold. Number one in 40 countries, earning a place in the 2007 Guinness Book of World Records as the album topping the charts in most countries.
Invincible (Michael Jackson): Number one in eleven territories worldwide, charted within the top ten in six other territories. 13-15 milion copies sold.
both are being considered. what hurts Invincible is that it came out to a lot of negative attention and never really got any love until he died and his work was re-evaluated (even then, it is still not considered anywhere near his earlier work). he was in the middle of a dispute with his record label, rushed some of the songs, didn't promote it with a tour, etc. it still sold very well because, well, its Michael Jackson. but it failed to do much else besides that. no real musical impact or influence (he didn't really do anything new on it, just fell back on the old formula).
pave, would you consider LCD Soundsystem? They have two albums that could easily make the list - "LCD Soundsystem" and "Sound of Silver".
they will definitely be considered. but remember, critical acclaim is not part of this criteria. musical impact is, and sometimes (only sometimes) they are connected. certainly LCD has some musical impact. but its also somewhat limited.
And another question, you want to expand the list to 200?
possibly. when we get to 100, we will see if there are albums that seem too great to leave off. right now, some of the albums listed on here don't really need to be on a "greatest" list to begin with.