Welcome delia*
I would base the wireless decision on your reading habits - if you think of a book you want, do you
have to buy it right then and there, or could you wait until you get home? A lot of people swear by Kindles, and being able to download a book right away. However they don't have a touchscreen device (as yet) and you're locked into their format. Other devices allow different formats, but you'd have to wait until you were home to add more books.
I'd advise you to read the forums here, and as others have said, look at your reading habits and see which device would work best for you.