The "3 EP's" CD is certainly allowed (and a good choice too I say.)
Basically anything that you could call "an album" is allowed.
Personally, I wouldn't vote for a career retrospective box set, but that's just me. Other people have.
The only things that have been disqualified so far are:
1) a single song music video,
2) a (joke) list of "Now That's What I Call Music" volumes 1 to 25 (that was a joke right?)