I was reading Steve Eichert's blog entry asking “if you had it to do all over again would you go into computers?“ Then I started thinking, if you won the lottery what kind of programming would you do?
I'd probably make an offer to John Deere to do work like this for free out of my house. They take real-time yield information from a combine and drive the equipment accordingly. Then they can take this information the following year and feed it into the planting equipment to vary seed density and fertizilizer to maximize yield over the field according to soil quality (and other factors). That is so freakin' cool!
Added thought: Add a little GPS drive system and farmers could be using this interface for their field work.
Otherwise I'd do open-source software and miscellaneous projects for businesses that I find compelling and try to turn them into good business opportunities in my spare time.