The original diablo, even though there is just one village (Tristam) and no other spot than the old cathedral, is the best diablo according to athmosphere and gameplay. I've been playing it extremely long and often as it came out even in multiplayer mode (ipx) and its still worth a try.
I would just give 10 points out of 5 maximum. Planescape Torment is the best game ever created in my opinion. The enhanced edition doesn't change anything at this perfect setup, wounderful story and awesome possibilities just makes it easier to play it without the need of mods, etc.