Well, even though the OS upgrade is free, there would be a big expense for software for me, as I still have software the needs Rosetta.
And it's an old MacBook with, I'm told, some corrosion on the inside due to having spilled water on it quite a long time ago. All the systems checked out when I took it to the Genius Bar a week ago and they ran full diagnostics, but they wouldn't replace the battery (which is the one item that didn't pass) cause of the corrosion. The battery still holds a charge, just not up to full capacity anymore.
So maybe I'll just stick with 10.6 for now.