Hit Points is a soundly established name that has gone a long way, so I don't really see a reason to change it just for the sake of change. If and when I come across other names in other systems, fine, I have no trouble, sometimes the names do give a different feel to the game, but usually if there is someone who isn't familiar with the system and its vocabulary, you need to tell them "That's the Hit Points."
I actually remember the first time I saw the term Hit Points written down somewhere. I don't remember what manual it was, but I do remember that first I didn't get what on earth it meant (I was pretty young...), then after a while I deduced the function, and then I laughed at it, hit points, what a funny name.... In less than a week I was using it like there was never been another term for it ever. And I don't know why but HP sounds really nice to me (my regards to Hewlett-Packard btw).
Nevertheless, I had to vote for ka as well! Perhaps I should use for my upcoming game a single hit point total for the entire party and call it ka-tet! (It would never fly, though, since only one of the players is familiar with the term, and they'd seriously complain about the lack of realism and meta-game the donkey out of it).
I don't know who suggested ka for a substitute, but they should be given a medal.
I want my Dark Tower RPG.