I follow eReaders very carefully and I can say that if you're seriously into reading books, the Kindle 3 is a very solid buy.
If you've never seen eInk before, you'll be amazed at how it's exactly like reading paper. It has incredible battery life (I'm talking a month/1000 pages). Plus the fact that you can hold hundreds of books and you'll never go back to reading a paper back.
The Sony eReader is also a good buy. The Sony bookstore isn't as good as Amazon, but you also have access to Borders. I like the Sony because I'm not a huge fan of the keyboard, but that's really just nitpicking.
The B&N Nook and Nook Color are both complete garbage! Watch out for these two. I've tried them both out and was very disappointed with them.
At the moment, there really isn't any eReader that handles pdfs very well. They don't scale right and you can't flip through them very quickly. But, the Kindle 3 is probably the best of any when it comes to pdfs.
No eReader is going to surf the web well. You can probably surf wikipedia, but because of the eInk, and the very limited hardware, you won't be able to go to many sites (this one, for instance). But, if you think about it, you can't surf the web on your copy of "Moby Dick" either, so it isn't much of a loss.