I've never tried myself, but I understand that the Sony Reader does work well in direct sunlight. Be aware however that some people have reported fading when the reader was exposed to direct sunlight. I've got no idea how prevalent that is or exactly what was done. I do most of my reading indoors anyway.
Kobo is a Canadian company who used to be owned by one of the big publishers. They were spun off and are now part owned by Borders Bookstores. The Kobo reader can be purchased from Borders and I think a few other places have advertised it for as little as $128. I know Borders had it for $149 with a $20 gift card. The reviewers gave it mixed reviews saying it was okay, but nothing special.
Be aware as well that the PRS 600 has the glare issue (i.e. it has a touch screen which causes glare.) Most people who keep them just get used to it and move the thing slightly to avoid the glare. That's what I've done. Others however, it drives them crazy and they can't stand it.
Regarding newspapers and the like, if you are interested in the text and not the pictures, you should check out Calibre (you should look anyway since it's a great piece of software for managing your library, but that's not my reason for mentioning it here). It can assemble a newspaper for you from hundreds of different sources all over the Internet. And it's all free. Though if you care to donate to the creator, I'm sure he won't mind.
Two other things: regarding waiting until October, the rumors are so far just rumors. Nothing has been confirmed as yet. Therefore, no one knows for certain what new features the new readers will have. And technically, no one knows for certain that they are even coming, though it does seem likely. However I can tell you that both the PRS 300 and the PRS 600 are on sale right now. You can save $20 on the 600 if you choose to buy now (had I waited a few weeks, I could have also, not that I had any way of knowing).
Also, I have no idea of the size of library you plan to use and for most people, this seems to be a non issue. However, if you're like me and have crazy notions of keeping your entire library at your fingertips, be aware that the Sony Reader has a weird design flaw. If you go over around 300-500 books, the time it takes to restart after you unplug it from the USB connection increases exponentially. It takes my reader well over an hour after I unplug it since I have over 3,100 books. Fortunately, I happen to have a PSP which uses the same charger and when I charge with the charger, it can simply sit in standby mode meaning you can just restart it in a second. However the reader itself does not come with the charger and buying the charger separately is an added expense. Again, this is a non issue if you don't plan to have more than few hundred books on your reader at any given time, but I wish I had known about the issue before I bought my reader. I find it extremely annoying, but I'm learning to live with it.
Finally, you may have better luck posting in the which one should I buy section since there is more info there.