This is anecdotal of course, but I have no qualms about paying a premium out of my own pocket to fly a preferred airline. Anything up 15% and I wouldn't even think twice - and I'd be willing to pay far more than that to avoid certain carriers.

Fast internet is something I would be willing to pay for on certain flights - either as part of the ticket price or as an add-on. Although most of the time I'm content to zone out to a movie or sleep.