The Kindle, the Sony Reader, or the Nook?

So recently I became interested in purchasing an e-book reader, mainly because I tend to read several books at once but despise the chore of hauling them around.

At first I only knew of the Kindle. But a quick visit to my local Best Buy introduced me to the Sony Reader. Oh no. Choices.

And then I read on gizmodo.com that Barns and Nobles is coming out with the Nook. More choices.

I really have no experience in this field, so which would you recommend? Or if you know of another, better e-reader, by all means tell me.

My main care is selection. I guess the next two cares would be memory and physical size. I don’t like bulky that much.