I will have to second both Dirt and In Utero.
And for me, the second side of Abbey Road is the ultimate musical flow. Of course, I'm a huge Beatles fan so that probably has something to do with it, but for all the reading I've done, and to know that the whole second side of this album was mostly done by Paul, alone, with others stopping by explicitly when he was not around to record, and then all ending with The End where everyone throws in their bit (one of my fav Beatles songs) is just something special to me, I guess. And yes, I know, it technically ends with her Her Majesty, but don't ruin my dream.
I will also have to add Pearl Jam's VS, which isn't really meant to be a concept album at all, but it's usually an album I won't stop once it gets started.