“We’ve made the internet in our image… Obese”
~ Jason Grigsby
“If your website is 15MB, it’s not HTML5, it’s stupid”
~ Christian Heilmann
“Good performance is good design”
~ Brad Frost
“Performance is about respect. Respect your users and they will come back”
~ Brad Frost

This is the fastest loading, most lightweight test I've come across. It's slick looking and it's pretty consistent.

Flash based network speed test, with included info regarding VOIP bandwidth