Entry level books/magazines/software/websites for a beginner
That's a really, really, broad question.  I can't give you a right answer, I don't know what you remember and don't remember from your masters' degree, and I couldn't answer all of those questions in one post if I tried.

However, since it's your first post, and since you can't learn the rules of the site without using it for a while, I'll try to help get you started.

For your car project, what you need to learn about right now is communication busses and automotive wiring.  A Bus Pirate or other development board for automotive communications (Would ideally have CAN, the venerable Bus Pirate does not, sadly) will help you interface various modules in the car, and allow you to develop custom modules for your car if you need that.  You'll need a DMM to check the voltage, current, and resistances between wires as you connect your wiring harness.  A solderless breadboard will also be a good tool to quickly and easily prototype low-speed digital circuitry.  However, you'll want a temperature-controlled soldering iron when it's time to actually build something.  An oscilloscope and/or logic analyzer are also great to have, but they're quite expensive.  

As far as websites go, this one is great! :)   edaboard.com, ladyada.net, and adafruit.com are other popular sites, but there are far too many to list.  You'll want to know a few distributor websites as well, like Digikey or Sparkfun from which to order your components and tools. I like the Circuit Cellar magazine, and I have a lot of books but it's hard to nail down a specific one that covers electronics in general.

I've never built a car, but I work at a company that builds electronics for cars, and I'm in a club converting a gasoline-engine car to a plug-in electric with my school.  A number of us are in the automotive industry, and a lot of us like to work on our cars; not sure if anyone's built one.  Most everything interfaces with a computer, and I've seen a lot of questions on household electronics and home automation.  I'm sure you'll get plenty of good answers for questions in all of those departments here.

I hope that gets you started.  When you have a better idea of what you think you want to do, feel free to ask for clarification and advice here.  When you have a problem with something you're working on, that's what we're really here for.