After seeing the price of the WiFi model I dived right in, and the news of a UK specific store helped my decision.
I love my 505 dearly, but the idea of being able to buy books on the device and getting samples, without connecting to my PC/Mac is very appealing.
I'm also looking forward to the improved contrast.
I feel like I'm jumping into the unknown though as I'm not sure of Amazon's ebook content. I just hope it's bigger than that of Waterstones! Also, despite the issues with Digital Editions / reader software and syncing with the 505, I kind of liked shopping around for books, so I hope Amazon's ebook store will be as competitive as their hard/paperbacks.
My only true worry is that my iPhone 4's ETA is August 24th, I hope they don't clash!
That's something else I will look forward too, the fact that I can read where I left off on my phone or reader.