Founders, what title do you use in email?
zach: All my business cards I've chosen when working for other companies say only "Programmer."  I like that.But when you're a founder or such, you have to cop to it.  You don't want it to look like you're evading responsibility or jerking people's chain.So it's "CTO and Co-Founder" on my business cards and (when appropriate) on email.