I have a 12Mbps cable connection. For the first minute or so, it peaks to about 18-24Mbps, and then stays at 12Mbps constant. 50Mbps service is available, but at a ridiculous price. So atleast the cable infrastructure around here is good for 24Mbps, proven.
I know that I'll be moving in the next few months, and it looks like FiOS is available in most of the apartments there. Only real advantage over cable is the upload speeds -- 2mbps versus cable's 768kbps. But I don't upload, so the extra 3mbps from FiOS (15mbps) is just an extra 25% bonus.
One last thing -- in the US we tend to have unrestricted download amounts. Comcast's 250GB/mo cap is one of the more notable, but still is an awful lot of data (on mere principles, I reject the notion of a 250GB/mo cap but that's another story). You'll find many of the superfast connections in other countries have pretty strict data limits, ones that you could exceed in a weekend of downloads. Just a general rule, though, I'm sure someone can find a non-US ISP with fast connections and 250GB/mo or higher data cap (or no cap!).