The first question I'd ask is - how often does your wife read books? Then ask yourself where she likes to read them.

I weighed the pros and cons of getting a tablet vs an ebook reader and, for me, the Kindle was absolutely the best choice. I read every day. I like to read in bed for awhile before going to sleep. I also read in the bath.

Tablets are heavy, tricky to find a waterproof case for, and hard to hold and operate with one hand. I'd been reading ebooks on a PDA for years and the backlighting gets hard on the eyes after awhile, making reading marathons of an engrossing book really uncomfortable.

The Kindle, on the other hand, is lighter than the average novel, can be operated with one hand (making it easier to lie in bed on my side & read), is light enough to hold in one hand with a coffee in the other, and can be read outdoors in the sun or indoors in the bath.

I've avoided one-purpose gadgets for years. In a house full of PC's, laptops, netbooks, phones etc etc I figured the very last thing I needed was a single-purpose gadget. The only thing I regret about buying my Kindle is that I didn't get one sooner! 10 days after I got the first one, we ordered another one for the household.

If your wife only reads occasionally and doesn't read in bed or the bath, and is happy to read with her device on a table or balanced on her lap, then a tablet may be worth considering. Otherwise, the Kindle really is the way to go.