I agree. As soon as I can afford to, I am doing the same. This is definitely a service, that I don't necessarily use a lot now, but if they went away I think the industry would suffer for it.
Everything they do inspires me to continue pressing on.
I don't totally agree with the "almost nothing". I was already using them for all my project and it was just enough for me. The second you have labels, you can mostly do any arbitrary complex structures.. But yeah, for medium to big project, that would not have been enough. Now with the new issues system, it might work.
I just got a GitHub paid account, not because I need private repos but because the company is so darn awesome.