I have an array of USB memory sticks, from 2 to 8GB which I used to use for photo's. Now I use them for everything and anything. I've never used the 'Safely Remove' icon and I've never had any problem with this method.
As for my external 80GB HDD, which I use for back up. It isn't powered through the USB, it is powered diectly from the mains. Which it is plugged into 24/7 but has it's own on/off switch. I only switch it on when I need to back some of my work up, then I switch it off.