I've written a browser-based visualization tool, profile_eye, which operates on the output of gprof2dot.
gprof2dot is great at grokking many profiling-tool outputs, and does a great job at graph-element placement. The final rendering is a static graphic, which is often very cluttered.
Using d3.js it's possible to remove much of that clutter, through relative fading of unfocused elements, tooltips, and a fisheye distortion.
For comparison, see profile_eye's visualization of the canonical example used by gprof2dot. For Python in particular, see a cProfile output example.