I bought one (16 gig, 3G) for my wife’s 40th birthday this year.
She had wanted a Kindle, then a Nook for some time
She absolutely loves it. Aside from all the reading she has been doing (via iBooks, Kindle and Barnes&Noble Nook apps), it has completely replaced her PC laptop and my old titanium powerbook.
Paired up with our home WiFi and our MobileMe account it is perfect for checking eMail, organizing events, web surfing, watching movies and tv shows, listening to music and podcasts and looking at photos.
And the 3G is great on the road. We took it on a weekend away and used the gps-enabled google maps all the time, used it as an alarm clock and ambient sounds to sleep by.
My daughter draws on it (with Adobe’s great free app) and plays air hockey and checkers and I read comics on it (with Marvel’s awesome app).
It’s really lovely to not have to be upright at a desk to do your computing all the time.
My heavy-duty graphic design work still gets done on my desktop mac, but everything else has migrated to the iPad.
I can’t say enough about it.