He seems to have been smarter than most, had more money than most, and cared more about how the world was going than most. Having a will might just have been being relatively reality-based rather than a sign of depression.
His online will is directly inspired by Eric S. Raymond's (whose example he links to as the good idea that inspired him), and ESR certainly isn't depressive.
Link
One of us is no more.
He deserves a eulogy more eloquent than what I am capable of writing. Here's Cory Doctorow's, one of his long time friends.
It's a sad world in which you are being arrested and grand jury'd for downloading scientific journals and papers with the intent to share them.