"Today" - Smashing Pumpkins. The song was written by Billy Corgan while feeling massive suicidal urges. The whole idea of it is to play on what he's saying.

"Today is the greatest day I've ever known, can't live for tomorrow, tomorrow's much too long" This lyric is about how he wants to commit suicide, and how he can't wait until the next day and he'll be dead anyways. I also just love how he says "can't live for tomorrow" instead of "can't wait for tomorrow," just a tiny detail I've always appreciated.