Then Windows 7 RTM 7600 came out, and I tried it, and it fixed the issue.
So I figured we now had two laptops, meaning I'd wasted over a thousand dollars but at least both computers worked.
As of yesterday? Well, the Toshiba failed a power-state transition, instead getting hot and running the fan on full when I tried to suspend it. I know from experience that this is the first stage, and it will be randomly dying in the middle of use within a week. The power state transitions had been absolutely fine before.
I'm going back to my "severely marginal hardware" theory. At least we have another computer now, since the Toshiba is getting closetized; it's obviously unreliable and not worth trying to fight with. I've got my netbook, now I've got my Nokia N810, I can borrow Rakeela's laptop, and of course we have the two desktops. (Only two. t'sChillin brought one when sie moved out here, but this was just in time for my older desktop to die; we merged the two computers into one higher-spec one.) There are probably enough computers to go around for most practical purposes.
I've already got plans for who I'm going to give the remains of the Toshiba to. I just wonder what killed it. In the meantime, I'll go back to being glad I decided to go buy the replacement.