Yeah the wifi's cool I guess but seems kinda gimmicky, and paying extra for 3G is completely beyond me. I didn't do tooooo much careful research, but I think the general feeling is that the latest kindle is still the best thing on offer, but there might be others available considerably cheaper given that you're in north america, so I guess that's worth looking out for.

It has native PDF support which has worked pretty well for me thus far. The big difference between PDFs and kindle ebooks is that you can't make the font bigger (such that the text is bigger and wraps automatically onto the next line) on a PDF, you can only zoom in (so the text is bigger but doesn't wrap, so you have to scroll across to read to the end of a line if you're zoomed in that far). That said, I'm yet to try a PDF that hasn't been a perfectly readable size without having to zoom in and scroll from side-to-side, especially if you set it up so you're holding the kindle sideways.

Somebody told me about a program called Calibre, which appears to be free, and that can apparently convert PDFs into native kindle format so that would get around that problem too.