Calculus has very little to do with Computer Science. I meant that Mathematical Logic will probably exercise your brain better than Networking for something like Digital Logic/FPGA design.

Thanks for the feedback; that's partly my motivation with wanting to take logic--if math requires me to think more, then I should take that, because developing good thinking habits is so valuable. But a bunch of the comments here suggest that the networking material is very useful, so I'm leaning towards that now. And you're right, I have my whole life to learn new things... but damn it, I don't want to be at a disadvantage! :)

I find that I learn things easier and deeper when I'm not forced to. Forced meaning I have to learn some person's way of learning the material, I have to know what someone thinks is the most valuable knowledge of the material, I would be influenced by the person basically...

Then again this theory of learn is completely out the window when it includes someone of expertise. I would be much happier and consistently motivated to take an intro to high-level programming class from Guido (Python) than some recent grad student.