I can't stress how much I agree with the last point. Probably the single hardest CS course I took in college was an upper-level seminar on compiler design, in w

I can't stress how much I agree with the last point. Probably the single hardest CS course I took in college was an upper-level seminar on compiler design, in which we built a simple compiler (for Appel's Tiger language) over the course of a semester. I've never poured more hours in to doing harder, more frustrating work in my entire life... and I've found that I haven't looked at code the same way since. I've found that you can get a similar experience by really, really groking C, but it still doesn't hold a candle to really getting to the innards of the machine.