Replying to Concept Albums vs. Rock Epics

I've always been a fan of both albums and songs centered around a story which really develops, and can't decide which i prefer. So, I wondered what people on NS prefer and why.

Examples of Concept Albums and some info on them:
General info and examples: http://en.wikipedia.org/wiki/Concept_album
Tommy, by The Who: http://en.wikipedia.org/wiki/Tommy_(album)
American Idiot, by Green Day: http://en.wikipedia.org/wiki/American_Idiot
Animals, by Pink Floyd: http://en.wikipedia.org/wiki/Animals_(album)
Metropolis, Pt. II, Scenes from a Memory, by Dream Theater:
http://en.wikipedia.org/wiki/Metropolis_Pt._2:_Scenes_from_a_Memory
Rock Epics:
2112, by Rush: http://en.wikipedia.org/wiki/2112_(song)
Echoes, by Pink Floyd: http://en.wikipedia.org/wiki/Echoes_(Pink_Floyd_song)
Achilles Last Stand, by Led Zeppelin: http://en.wikipedia.org/wiki/Achilles_Last_Stand
A Change of Seasons, by Dream Theater: http://en.wikipedia.org/wiki/A_Change_of_Seasons_(song)

I know I haven't given all the examples of each, but should be enough for you to form an opinion if you don't already have one. Also, suggestions for others would be greatly appreciated, as I'm always looking for new music.