Ask HN: What's the best way to graph stuff on web sites?

So I've been picking through the various frameworks for displaying graphs (Google Charts, Yahoo Charts, Flot, etc). There are lots of possibilities but they all seem bare-bones to me. In that you need to do a fair amount of data manipulation before you can start using one.

The real challenge I'm having is hooking up my data to a model to present a sensible visualization. One of my primary sets of data is a series of response times. I want to throw the series of times (in milli-seconds for example) at an API which will create the a graph of the best trend to represent that data.

I've been trying to brush off my college statistic to hand roll something, but maybe someone knows a better way...