The Kindle doesn't natively support pdf files, and I have yet to find a good program to convert them into a format that it does support. Typically they lose much, if not most of their formating when they are converted over and become difficult to read without effort. The best work around that I have found so far is to cut and past from Adobe to Word and save as rtf file until you get it formatted in the general way you want it, then save that file as a txt file. It's a major pain, and I hope Amazon resolves this soon, as this one of the things I really envisioned the Kindle doing. It would be awful nice to show up to a game session with my Kindle, rather than a big heavy pile of books that I MAY need to consult. It would be especially ideal for convention gaming, if it did a better job of converting pdfs. If this is your main objective, I would almost say invest in a decent netbook instead, at least until Amazon works out this wrinkle.
As far as general reading goes though, I absolutely love it! I have found myself reading constantly, and it's great to be able to finish one book and download another in a minute or two and start again. Plus I can check my gmail wherever I go. Heck, I've used Google Maps on the go a couple of times to get driving directions when I've been lost. Overall, it's a great little gadget.