Speedos should be scaled like the tacho is. Personally I'd rather they just do away with the speedo, it doesn't add anything - I haven't seen one in a F1 car for a while. Racing isn't about speed in normal circumstances, it's about relative speed - all you want is for your car to be faster than the opposition. It seems a pretty integral part of the HUD however so it'll be there, and it'll keep people happy to be able to see how much they're breaking the speed limit by.
I'm 17, all my friends have recently gotten their license (as have I). They all drive at 130km/h when they're technically limited to 90, and they do so in crappy 10-15 year old cars that look, sound and feel like they'd fall apart at 70. Each day I wait to hear one of them has killed themselves, and I feel no remorse or regret about it, because they'll have deserved it for being reckless. My dad is an ex racing driver and rarely speeds by more than 10km/h. He, as do most people, recognises that excessive speeds are for professionals in a safe environment, not normal roads. It doesn't matter if you're Juan Pablo Montoya or Michael Schumacher, all it takes is one person to not look in his rear vision mirror before changing lanes and quite a few lives are suddenly in the balance.
I've sped twice, by about 15km/h, to overtake people. The 25 seconds it shaved off my drive wasn't exactly worth it. I know the adrenaline rush that comes with it, but personally, it's not worth the risk to myself, my license and others.