This is so wrong, but somehow, morbidly amusing. I certainly don't think the adds are obtrusive enough to have my sig read "suicide death 9/11 murder", but each to his own...
Thunderbird seems like a more elegant, cheerful solution.
What you'd really want to do is work the advertisement extermination into the body of the email inconspicuously. Say I'm mailing my friend Katrina about a concert I'd kill for tickets to--I make an offhand reference to the financial crisis, a tsunami of corporate catastrophes, how the markets quake in fear of another fiscal tragedy. Just like that, an advertisement genocide. I'm sure it'd soon become as natural a way of writing as e-prime.
