Pragmatic Programmer books for your Kindle you have the choice of buying from Amazon or buying direct.
Buying from Amazon is the path of least resistance since you can buy right from your Kindle.
But if you do that, you'll end up with a proprietary format with DRM that only works with your Kindle. (Although you can read them on your PC or iPhone or iPod Touch with the Kindle app.)
Instead I'd recommend buying direct. That way you can download the book in multiple formats - PDF, ePub (e.g. for iPhone or iPod Touch using apps like Stanza, or for Sony readers), or Mobi (for Kindle). The books are DRM free, and as a bonus, you can download updated copies when they come out.
I've bought a few eBooks from Pragmatic Programmers in the past, either on their own or together with a paper copy. It was very nice to be able to go back and download the Mobi version so I could have them as a reference on my Kindle.
The only very minor hassle is that you have to buy and download the books on a separate computer and transfer them to the Kindle. In Canada that means by USB since emailing to your Kindle is not supported here.
Thanks to Pragmatic Programmers, at least a small part of my eBook library is not locked to the Kindle. I hope more publishers follow their example.