I wouldnt want cellphones on flights. When people have nothing better to do or entertain themselves with they start calling people. I cant imagine sitting 6 inches from somebody (as you do in coach) and them talking on the phone for hours on end.

As for internet, I would pay a premium for access to it. The internet is much more private and doesnt disturb anybody else around you. I wouldn't even need to keep in touch with the office on flights, I would just use it for entertainment value only. I'd easily pay the $30 for 10 hours of entertainment on a light to LHR!