I have a very good knowledge of electronic concepts, but I have yet to work with microcontrollers (I think they would be useful in some of the switching power supplies I am designing). After some research, I think that Atmel's ATmega and ATtiny series would be most useful to me. Does anyone have any recommendations for a good starter kit that would include programming software, a development board, and a beginner's guide? I'd prefer it to be USB compatible, since I've heard that USB to serial adapters can cause problems with programmers.