I've got the first-run kindle and still use it daily. Battery life is awesome. (How's the battery life on that iPad? 4-5 days?
)
That said, my gadgetitis forced me to give the nook a good once-over. It's solid, but I couldn't find enough of a cause to switch.
One thing I will say, is the nook allows you to read freely from Barnes & Noble's catalog if you're physically in the store, which is neat if you're hanging around in B&Ns alot.
But between brand loyalty and familiarity I have to vote for the Kindle. It just does exactly what it's supposed to do, the way it's supposed to do it.