I try to keeps our numbers under 1 second, although we only target the USA.
The biggest improvement to our page load speed came from using a php cache (xcache) and specifying client cache lifetimes. The first got us to around 1 second and the second meant that the best case (which happened often) was about 0.5s
I just complained to one online cartoon about this, changing from strip to strip takes 1,5 seconds and that's super slow afaik. It really annoys users.