I think part of the answer depends upon you. That is, if you have a boatload of money, get the best hardware you can. If you're like most of us, shop around. Personally, I want to support Atmel so I started with a "true" Arduino. For prototyping and things like that I now tend to look on eBay. I've bought a bunch of stuff from China and it has all worked well. You can buy an ATMega1250 for less than $20. The other issue is how well do you know C and does that influence what you want to do with the Arduino. If you're an experienced C programmer, then everything becomes a hardware choice. If you aren't a programmer, then you need to blend the hardware and software learning experience. One kit probably isn't going to be a perfect solution. Like they say: If the only tool you have is a hammer, every problem starts to look like a nail. Personally, I'd look at myself and ask what do I need to learn, then I'd buy an inexpensive Arduino board, a programming book or two, and whatever hardware is necessary for those projects the peak your interest. My guess is that you could get a book book suited to your background, an Arduino board of some sort, and a handful of components that look interesting to you for much less than the price of the kits you mentioned.