[ndixon]

Mainly one very prosaic reason: my Kindle has a few grey blobs on the screen where I've dropped it onto hard objects or dropped things on it and the ink has somehow bled; I wanted a cheap replacement and the STR is under £30 in the UK right now, so it's cheaper than buying the Touch or even the basic Kindle.

Secondary reason is that it supports EPUB and I like to keep my options open.
I also wanted to try a touch screen, and at this price it was worth a gamble.

I like the touch screen, the keyboard works really well and is much better than navigating with the Kindle's 5-way controller. The range of fonts is nice too.

I like the Contents page and easy chapter navigation; I also like the "pages left in chapter" in the "Go to" window.

But I'm mostly noticing differences that I dislike at the moment:

Dictionary
With the Kindle I can choose other dictionaries (just by nominating a book), and have a different dictionary for each language; I have a translating dictionary for German (German headwords, English definitions) which is a big help when reading foreign language texts. This simply isn't possible on the Nook, even though parts of the interface seem to be designed for multiple dictionaries.

Layout
The Home screen might have showroom appeal, but it really isn't useful to me. I don't need it to look like a jazzy magazine cover. The area I use most often is the Library and that only shows six books at a time because of all the headings at the top.
In comparison the Kindle UI feels cleaner, more efficient, and packs in more information.

I don't hate the thing – I may grow to love it – but just now while it's still new I keep noticing things and thinking "Oh. Why did they do it like that?"