[PHP] Graphing tool

[Augmented]

I recall there was a good post on this a while back, but it appears to have been pruned. Quick question really. Which open-source graph tool, like GraPHPite or PHPlot (which I've used before, and may go with), would you recommend?

Looking for something that doesn't plaster its URL or such on the generated images and has a decent (OO, if possible) API.

 

[Augmented]

Thanks for the suggestions, just the sort of thing I'm after. Should get a chance to check them out on Monday, so I'll see how I get on with them.