That's definitely helpful. I've had a friend who had a crazy image stability feature that shot good pictures while basically waving the camera around. I also didn't know about the ISO spec, but that's definitely helpful. I'm assuming you can change what setting that is at so you don't let let in too much light while you're, say, outside.
My girlfriend has a Powershot A530 and my mom has one thats a little bit better and I've always liked those. Checking on newegg, the SD850 is going for about 300, so that's out of my range, but the A570 is going for about 173 and I get a free SD card, too.