When is comes to internet service, is there really a difference for the general user at all? If you do big games or downloads, then maybe you'll want to fork up the dough. However, so many people use the internet for the bare minimum: email, Facebook, maybe banking and a few other things. Sure any modem whose speed is measured/advertised as a 'baud rate' (google it...) may not be sufficient for the amount of data packed into a contemporary web page, but most don't need the fastest option.
Despite that, I'm sure a good portion of internet consumers out there opt for the more expensive option, and I'd also bet they wouldn't tell the difference between that and one of the lower tiered options. Why? Because companies like Cox and Qwest advertise it so heavily!
It's a shame that so much money is wasted on non-appreciated services.