[jocampo]

Engineer here, reading computer and technical books most of the time.

The bad news, maybe you know this already. PDF is not an ebook format. There is no ebook reader out there that can give you a decent experience, and with "decent" I mean not a reading experience, but interaction, writing notes, editing, etc.

The good news: an iPad with Goodreader can give almost you need for a rich PDF experience. I used to own Kindle DXG. It was good for reading PDFs, but nothing beats the iPad plus Goodreader app. Not only you can make annotations, but gives you color. It can be a distraction too, but if you're on a tight budget or want an only device, the iPad can be a good choice, even 1st gen. iPads.

Now, for a true reading experience, nothing like an eink device. Of course, you will need good ambient light, but it is easier for your eyes and they have better battery life. The drawback (or good, it depends) you cannot browse emails, Internet, or use it for much more than reading a book. Some let you access webpages, but the experience is very limited.

My successful combo: iPad2 for technical books and PDFs and Kindle 3G with keyboard for regular text books. In some cases (increasing because boom of ebooks) most technical books can be read on Kindle 3 on landscape mode if they have been properly formatted.

By the way, for content creation, no tablet is good enough in my opinion, not only because keyboard but because available software for that. The one that gets closer is the Transformer, but you may need a serious netbook. I personally like the Mac air, but we're talking about serious money investment.