I voted for the Pumpkins. Siamese Dream and Mellon Collie are just 1-2 as the Pumpkins' top albums and even though I wouldn't call this the soundtrack of my teen years, I find that SD is still as enjoyable to listen to now as it was way back then.
I liked SOAD's first album, as it sounded fresh for a metal scene diluted with nu metal, but then again heavier strains of metal diverted to the underground and so, I digress. I liked Toxicity more, but felt they had peaked there and I see SOAD more as a novelty act, like Slipknot and Marilyn Manson.
It's kinda like the Old Cafe - http://fbc2.freeforums.net