Wow, good tips; lots to think about.
I try my best to keep up with the latest technology, so Epub 3.0 seemed the way to go. But I'll have to take another look at it.
Anyway, I now have three tables of contents.
P.S. Now I remember why I was so fixated on Epub 3.0. I watched a series of InDesign tutorials @ Lynda.com, and I think the instructions were to choose Epub 3.0. I imagine the folks at Adobe would favor Epub 3.0 because it shows off whatever InDesign is supposed to do better than 2.0.