I am not sure what you meant under Storage but the simple touch has access to all your ebook purchases from the b&n 'cloud' just like the kindle. you 'archive' books you are done reading and they are removed from the device (cover art remains) and re-download them when desired via built in wifi. Does the kindle have some sort of advantage here?
P.S. this is the first side by side i have seen, thanks.

Why does no one who reviews Kindle v. Nook ever talk about the real issue? If you buy a Kindle, you have to buy your ebooks from Amazon; if you buy a Nook, you have to buy your ebooks from Barnes and Noble. How do the prices compare? Selection? Yes, both have hundreds of thousands of titles, but they aren't the same. If I bought the top-100 best selling ebooks on both services, what would the relative cost be?

unfortunately the Paperwhite is not being sold in the UK - why not??!?

Next thing they ought to do is make them so that you can write notes in the "margins". Or highlight the text. hey - I don't have one, so maybe they already do that. Maybe they could download coloring books for the kids....

@Steven Guillion most reviewers do not note the differences of the ebook markets because they understand you are not actually bound to them. I buy from both markets, or from other markets, whenever it suits me. You just have to convert the file formats, which is absurdly easy and usually free.

@ KMH: I have a Kindle DX. It allows you to highlight text. And, it allows you to see which lines of text other customers have highlighted (thus alerting you to crucial or famous passages.) My kindle also allows me to add notes. I don't have a Nook. But YouTube has videos describing Nook's highlighting and note functions. See: http://www.youtube.com/watch?v=shs10WzKLGs

Once difference between them is ergonomics. In particular, the Nook has page up/down buttons in its bezel that allow for very efficient reading. It is actually easier to read than a paper book.
As for the kindle vs nook store issue, my experience is that about 6 times out of ten, the same book is available in both stores. About once out of ten times, a book is available on the Kindle store and not on the Nook. And about three times out of ten, neither one has it.

I would want to share my exp. I have bought two kindles and actually seen three kindles, and all of them ended frozen in less than a year, I would call it a bad investiment.....

@JPAR Paperwhites (WIFI ONLY) are now available in the UK at Waterstones stores nationwide.

I have had both Kindle keyboard and Nook 1st gen then switched to the Nook Simple Touch. I much prefer the Nook. For starters the customer service rocks!! I also like being able to side load my books and read with out having to go online to pull a book from the "cloud" I am considering a slight upgrade to a lighted model and will have to research carefully. I love that the Nook ST with Glowlight is lit from the top as if a lamp was over your shoulder. I am rather sensitive to the bright back-lit screen on my laptop and am concerned that the Kindle Paperwhite might be similar. Any feedback on this???