Cracking episode! Brilliantly timed for me as I am just starting down the path of AVR programming.

I've bought several programmers, usbtiny, libusb, usbavr, avrisp2. A lot of them seem to be less than perfect clones of known designs and they spit out what look like error messages that you can suppress with the -F flag and then carry on working.

Fuses are confusing but there is an online fuse calculator, I'll look it up and post the link if you haven't found it.

I didn't know about avrdudes and I will look at it. But a lot of GUI programs are written with inaccessible toolkits like Qt.

Arduino IDE is itself inaccessible, so I stick to the command-line. Take a look at arduinino.mk, which is a Makefile system you can use with programmers to avoid the Arduino IDE
My first project is an audible logic probe. Had a logic probe with LEDs for years but that's useless to me now of course.

I'm jealous of all the little gizmos now appearing with cheap and colourful displays, like your transistor tester.