Well, I finally got LA Noire downloaded and installed. I was so nervous those last few minutes! "Don't fail. Don't fail. Don't fail."
Three full days to download this, going day and night. I think I need to turn my poor computer off for a deserved rest!
I did some checking though, and apparently you can backup/transfer a downloaded Steam game to play on another computer or reinstall if needed, without going through the whole download process again. I will definitely back up my games just in case.
Here's a guide to that: Steam Game Backup
Oh, and BTW, my DH asked me about the slow speeds my ISP was giving me. He says tomorrow he's going down there in person to ask why he's paying full price for half a service. HA!