Cairo feels a lot like OpenGL
I got a simple spike test done for PyCairo usage. Mostly this is just me figuring out how PyCairo works and how it and PyGTK interact. No big deal right now, it takes turtle commands from the turtle object's queue (produced by Python source running in a background thread) and translates them into simple Cairo operations. Does scaling and centering so that the resulting image is always on-screen, but that's about it.
Cairo is lot closer to Turtle graphics than PyGTK. It basically feels like a cut-down version of OpenGL... which makes me want to reach for OpenGL when I'm working with it. Cairo also feels a lot like Turtle graphics , simplistic state, not much feedback support. Should see whether GooCanvas or the like allows for higher-level operations (e.g. easy drag and drop, selections, that kind of thing) without making it hard to get back to the base level.