As someone that has been working in the computer industry for more than 10 years now, I fully agree that compressed air is fine. I use it regularly on system here at work. I've gotten to the point where I can angle the can to get the dust out of the HSF units and out of the case as well, so don't worry about it getting into other components.
If your case is located in an area that is prone to dust collection, a little secret that some people use to help minimize the dust build-up is this. Take a used dryer sheet, and simply attach it to your computer case over any intake fan vents. Once they are used the sheets are quite pliable and breath well...sort of a do-it-yourself filter system. It won't stop all dust from getting into the system, but should help reduce how quickly it builds up and requires you to clean your system.
If your case is located in an area that is prone to dust collection, a little secret that some people use to help minimize the dust build-up is this. Take a used dryer sheet, and simply attach it to your computer case over any intake fan vents. Once they are used the sheets are quite pliable and breath well...sort of a do-it-yourself filter system. It won't stop all dust from getting into the system, but should help reduce how quickly it builds up and requires you to clean your system.