I'll repeat the common theme around here: Why didn't they teach stuff like this at my high school?
Even though I did two senior computing subjects, and "learned" to use everything from Frontpage to Pro-desktop to Access, I consider myself entirely self-taught. The programs I consider truly worthwhile (Flash, 3DS Max, Visual Studio, etc.) were barely touched upon.
I only found XNA recently by sheer blind stumbling-around-running-into-walls luck, but I'm not going to waste the opportunity.