Some of these are repeats... but they deserve being repeated!
- Don't download programs from the Internet. This rule is difficult to follow 100%; just be aware that each new program you download and run could be the one that steals your BTC.
Have there actually been any cases of people downloading software and having their BTC coins hacked? I know there's a lot of 'automatic bitcoin' software out there that are obvious scams, but I'm saying more subtle things like Alt Coin wallets, someone downloads an Alt Coin wallet installation and all of a sudden their BTC coins are gone. Any cases of that yet?
Yes. This has happened many times.