Shoechick, and for those still deciding...
IMO, if you're looking for something with the functionality(touchscreen) of the 700 and you still want decently crisp and readable text, the 600 is fantastic. As I mentioned before, it IS better than the 700, just not as crisp as the 505/300.. it's really right in the middle. And the glare is more harsh than on the 505/300, but still probably not *quite* as bad as the 700 (I've not owned one and only played with it for a few minutes).
I decided to keep the 505 for a few reasons. The screen and text resolution is simply second to none. It is CRISP and the background "paper" seems whiter than those with a touchscreen, so to me, it felt much more like I was reading a book. I liked that it comes with the case as I bought a $20 LED "Mighty Bright" light for it that needs a cover to clip to. It works fantastic and I highly recommend it - Chapters/Coles/Indigo for us Canadians. Thirdly, and perhaps most importantly, I'd have to pay more to get a 600 AND then buy a case AND wait for it to arrive. All those factors combined made me think that the extras I'd get - touchscreen, note-taking and the dictionary didn't make up for those negatives. So I stuck with the 505.
Another minor thing I noticed that may/may not be a big deal... the 600 & 300 are both thicker than the 505. The 505 is about 1/3 thinner than either of them. Not sure how they pulled that off.
For those that already have an ebook reader and are considering/pre-ordering the 600 in the hopes that it will be SO much better, hold off if you can. You may be a tiny bit disappointed. Yes, it's better, but wait till you see it in person to judge. I suspect that you'll stick with your current one, if text crispness is an issue.
Oliver