"Retro Repair" key electronics skills?

[Swift Griggs]

I figure I'm good for about eighty hours or so of reading and fooling 
around with electronics before I'll want to move onto a different hobby 
for a while (I rotate through a whole bunch). That's my normal MO. So, I'm 
wondering what kind of skills I could build with that time, once I get 
started. I'd love to hear if anyone has suggestions for how to use my time 
wisely to learn skills that would be most useful for working on older 
machines (mid 80's to late 90's is my focus as far as a hardware 
bandpass).

Here's what I (think) I know now:

- Basics about electricity. Ie.. Ohms law, power vs frequency, etc..

- I understand basic physics ("A" in 100-level college course and two 
  years of high school physics, too). I actually had an excellent teacher, 
  too! 

- I used to do math to about a 300-400 level, but now I'm at a 100-200 
  level (I can still do most algebra II, some trig, and a few other bits).

- I understand what most analog components do (resistors, capacitors,
  diodes, etc..). I can run a volt-meter, and super-basic operations with 
  an analog scope (checking test points and that kind of simple crap) . I 
  also have a rudimentary rig for soldering etc... 

- Since I'm a coder, I understand boolean logic (which I hope would help 
  with ICs). 

- I took a digital electronics course in college. However, it was pathetic 
  and it's all gone now anyway.

I've spent most of my technical energy learning coding and sysadmin 
skills, not hardware. I'm still interested in it, though. I'm most 
comfortable with self-teaching via projects. Any that you folks would 
recommend (even if they are for kids, I don't mind, I'm not proud) I'd 
love to hear about them. Books, project kits, etc.. My goal would be able 
to understand 40% of what is happening on an Amiga 500 or that level of 
machine. If I could do that.... wow. fun. cool. Plus I bet I could repair 
many more items/problems than I can today.

-Swift