Well, I used to have the album, but it was taken away from me by my mother when she heard the line "Emptiness is loneliness, and loneliness is cleanliness, and cleanliness is godliness, and God is empty just like me." It offended her delicate Christian sensibilities I guess.
Anyhow, I just downloaded it again the day before I made this thread, the first CD, not the second (damn you dialup), and I'm basically appreciating it a lot more than I did when I was twelve.
As for answering what is so awesome about Billy Corgan...well, not much.
I heard his solo album was okay, but Zwan really wasn't great, even though it totally had some awesome musicians in it. His only real accomplishment is forming the Pumpkins, who were totally awesome.
I can't speak for their other albums, but at least Mellon Collie, is one of the most complex, if not the most complex rock album I have ever heard. I cannot even begin to imagine how complicated some of these pieces must be to play, and the layers upon layers of guitar and bass, blended with everything else seem to me more like a symphony orchestra than a simple rock band.
I mean, rock music is good and all, but most of it is just a group of chords repeated more or less over and over again the entire piece, it gets boring to listen to after awhile, no matter how totally sweet and awesome it is (pretty much any* Green Day CD is a good example of this).
Mellon Collie I can pretty much listen to over and over again, and it doesn't get boring.
Then you start to look at how much variation between different genres there is just on this one double disc album, and it becomes pure concentrated awesome (there is so much variation that when you look on the P2P ID3 tags they can't even decide what genre it is).
So, yeah.
*Warning! does not exist, it is a figment of your imagination, a very, very, bad figment of your imagination.