My local copy of Firefox is annotated to dump a bunch of network stats when shutting down. One of them is a CDF of HTTP handshake times. This is from my desktop, which is connected to a premium cable broadband consumer Internet service. It's not as awesome as FIOS, but its still at the top portion of what a home consumer will have in the US, which in turn has certain geographic advantages when connection to many hosting companies. Its fair to say my performance is going to be at least a bit better than the average Internet user. And it is still slow. (We of course need to work to be able to better characterize what the real spectrum of experience is.)
This isn't scientific. It is where I happen to browse, and its just one datapoint although I can tell you my gut says it is pretty typical output - gathered over 15,000 connections.
Only about half of my handshakes are where I want them to be: < 100ms. Most of the rest fall in the next 300ms. To be fair there is a little skew in here because the code doesn't separate https from http, and SSL has an extra RTT in there. But SSL is a small fraction of the overall sample.
And this is the desktop. Think mobile and wireless.
Latency matters.
