Loads of unlimited data plans out there, though some at pretty low speeds.
So it seems to me that in order of best to worst service for price it's:
Europe
South America/Middle East
North America/Asia
Aus/NZ
Africa (though that's only based on one sample from South Africa)
I say we all beat up on the Europeans!!
Pretty small sample size for Asia and Africa with vastly different countries.
I know both the Aus and NZ governments are working on getting ultrafast broadband around the country to improve internet speeds, but I doubt it will improve price, hopefully it will allow unlimited data plans (you can get unlimited data plans if you go for 56Kbs dial-up, but that ain't broadband). Aus, NZ and USA are looking at laying another transpacific telecommunications cable which should also help with international communications speed and quality. But all that comes at a cost to the user.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
