Ok so something's prompted me to try to render the most photo-real reflective-sphere-on-a-checkered-plane that I can. I'm pretty happy with the result. I'm rendering the final 1600x1200 version now, it's about 50% done after 8 hour rendering! Will upload when it's finished...

In related news, I've just found out a mate of mine has been creating very useable HDRI probes. Check them out at [link]

[edit] here it is: [link]