This response is sort of what I was expecting. Personally, I don't think we could handle NO speed limit (right now). If the government devoted some serious effort to driver education, road maintenance, and vehicle inspections I think we could get there (but likely never will).
I do however think that many interstate speed limits need to be reviewed. When you see over half of the vehicles on a given roadway exceeding the posted speed limit I think you have a major problem.
This article pretty much sums up my feelings. It's an interesting read if you have time.
http://www.motorists.org/speed-limits/do-limits-matter