Personnaly I've just came through the same questioning and choose the Kobo Glo (I'll get it tonight!!!!!)
Four readers were in competition:
- Kobo Glo
- Pocketbook Touch Lux (brand new, open "software wise")
http://boutique.pocketbook.fr/product.php?id_product=58
- Cybook Odyssey HD Frontlight
- No Kindle, because of the epub story. And I don't like when it is really not open.
I went for the Glo because of the screen. I've tried one of my colleague's Odyssey HD Frontlight and screen is "too grey" for me (but still very good, but as I am coming from an e-reader without touch sensitive layer, I was deceived). It's a very good reader anyway. As a first choice (and even second

), You won't be disapointed.
The Pocketbook Touch lux looked promising, but it is said that the screen is as "grey" as the Odyssey. I skipped this one as well.
So finally, I ended on the Glo, which seems highly "tweakable". Good for a nerd like me.

And just do what you're asking, means reading.
The best option is to try to borrow one that you can use for one week, and make your opinion on what is important or not. A bunch of appealing features can really be useless in reality. If it's your first one, any device you'll choose, you'll be happy with.
But if you can be "VERY" happy. That would be better.