Just be aware that there are some magazines only available on the e-ink Nooks at this time.
The New Yorker is the one that I'm aware of; there are probably others, but I haven't run across them.
The nook app itself is pretty much the nook app across the Android platforms. I prefer it to the onboard reader on the NC and Touch, but it's uninstallable on those, or has been for most of their existence.
In the 10" tabverse, the Lenovo K1 tablets are good buys. At around 350 if you shop around, you can get a dual-core with 1G of RAM and 32G of onboard storage. That's a very good value.
At 400, you can get a Transformer or Iconia or whatnot, but I think the 400 dollar configs of those have 16 or maybe even 8G of storage and only 512 M of RAM.
All of these are going to be pretty fast and have reasonable displays and run some kind of Honeycomb, so I guess the big thing to be sure of is that the Nook app will run in Honeycomb, but I'm pretty sure it does.
It would be the iPad, IMO, due to the screen ratio (I have an iPad 2), but the resolution is too low. Transformer (like most other 10" androids - 16:10 1280x800), which I also have (stupid me, lol), better, but there is some cutoff. Also, the resolution is still not high enough, but much better.
But the TF is a bit heavy. The TF Prime is much slimmer and lighter, but not expected till early December (already announced for then, by ASUS itself). Maybe a Galaxy Tab will do.