Hands down, no question about it, the Nook SimpleTouch with Glowlight is the best e-reader on the market.
It boasts a bigger battery, a faster refreshing display, hardware buttons AND touchscreen controls (Amazon forces you to choose between touch screen OR hardware buttons - no exceptions), and of course a backlit display.
No two ways about it, this backlight is the most impressive unchallenged feature of the Nook.
While traditional e-readers require an outside light source - like a physical page does - the Nook was able to purchase impressive backlighting technologies that make it possible to read in the dark - without interrupting any neighboring slumberers. The light on this thing is soft - it wont be any more annoying than an occasional phone glance at night - and possibly less intrusive.
In daylight, you can almost not tell when the light is on. This would be a problem if it weren't for that gargantuan battery - even with the light left on, the Nook can last for a very long time.
The Nook comes with 2GBs of internal storage, or up to 1,000 books. Unlike the Kindle, it also packs expandable memory, up to 32GBs, which is - a rough calculation here - all the books in the entire world.
The Kindle has a slightly larger amount of internal storage (or even more likely, smaller book sizes), as it holds up to 1,400 books.
Truthfully, the ease of downloading/deleting/redownloading on these devices makes the internal storage a bit of a moot point. It's not as if you're going to have any trouble fitting all your vacation books on the devices, but if you absolutely must have more than 1,400 books at any given time, the Nook is your best (only?) choice.
There's also the matter of refresh speeds - an area the Nook clearly surpasses the Kindle Touch. While flipping pages on the Kindle is hardly painful, the Nook's is quite a bit faster.
This is especially noticeable when you must use the device's software keyboard.
Depending on how you use your device, you can almost get away with never using the keyboard - on both devices you can buy books on your computer and beam them to your e-readers, scroll instead of search for your books, and write notes elsewhere.