When I was at Georgia Tech, I got 650 Mbps. You realize the bottleneck isn't your connection at that point -- it's everyone else's. Which means a lot of sites still download just as slow. Although the big sites have optimized data centers, so it was pretty cool downloading an entire OS in a few seconds (although I think my hard drive write speed limited that a bit too).

My father works in the fiber optics industry and has told me that if fiber was brought directly to each home, every person would have more bandwidth than they knew what to do with. One thin, tiny fiber can carry an INSANE amount of information. The problem is the processing circuitry that converts these light signals into digital signals. These NICs have a much lower throughput than the fiber itself, but if the fiber infrastructure was already in place everywhere, upgrades would be much cheaper and quicker. (In other words, Google Fiber has easy upgrade potential to 10, 100, ... Gbps).