I'm not going to jump on the "Government has no right telling it's people what to do" bandwagon, but I will say this: There needs to be something done about the speed limit situation. Much of the research simply does not back-up the reasoning behind those limits.
There are some people, from what I have read (and you should know who you are), who feel like that 'cannot' seem to control their car at speed.
Easy solution: Keep the hell out of the left lane, please.
So here is an idea: What about graduated licensing.
Those who don't feel confident with their driving; i.e. a couple of people who posted in this thread, would have a D-Class license. This would allow them to drive only during daylight, at speeds not exceeding 45mph. They would be forbidden to travel on interstate, mulitlane highways. They would be allowed passengers over the age of 18.
C-Class license: This would allow both night and day operation, at speeds upto 65mph, and only allowed to use the right-hand most lane of highways. Allowed passengers of any age. Only during heavy merging would this person be allowed into an 'other than right-hand' lane, and then only for a distance not to exceed 1/8 mile.
B-Class: The above but changed to allow for speeds of up to 130mph, and can use the center lane for travel, left-lane by exception.
A-Class: Up to 175mph, No lane or travel restrictions.
NR-Class: No speed restriction; Drivers are allowed to pass on any available piece of concrete - as long as it's to the LEFT of the person being passed. This includes shoulders and medians.
Obviously the people with the NR, A, and B class licenses will have the proper training and certification. This is easy achieved by taking classes and being graded on practical application.
If they can restrict your driving because of eye-sight, they certainly should be able to allow certain drivers a speed consideration due to ability and training.