Sarah,
Thanks for that great list! I get around reasonably well, and even have my own list, and was only aware of a few of these.

I am a fan of a couple paid frameworks, but free themes really have come a long way. With greater quality control on the mothership, along with so many generous and great coders, there are many very hot ones available, ones that I wouldn't hesitate to recommend. I, too, have recommended Underscores to people who clearly will benefit from that as a base.

Regarding paid theme support, no two companies are alike. Some have better code support than end-user support, for instance. One of the most popular theme companies doesn't really have much of either, IMO, and I'm sorry I ever used them. It's kind of like hosting where everyone claims to have 110% uptime. :) Say anything to make the sale. I'd go so far as to say that some paid themes support is worth almost zero anyway, so why not try something free?

I'm very self-sufficient, so I'm OK as long as the code is high quality (and better yet, clear enough to modify easily). If I needed lots of end-user support, I would most likely be just as unhappy as the hordes of newbie theme buyers whose complaints I see in the forums.

Make, by Theme Foundry, is another nice freebie worth checking out, that allows quite a bit of building without genius coding skills.

Thanks, Dave