I would go even further and say that guests are going to start expecting not just free internet, but free *wireless* internet.
I'm currently at a meeting at the Bethesda North Marriott, which is clearly positioned as a business hotel. From what I've seen and read, while the public areas do have wifi, the rooms have only wired ethernet connections (@ $12.95 per day, no less).
Have these properties noticed how many iPad's Apple is selling recently, and the lack of an ethernet port on any one of them? Same with the MacBook Air (although a $30 add-on accessory is available).
If I can now get wifi when flying at 40K feet, is it too much to expect it when I arrive at my room?