I would post a really long dissertation on electronics, but I am on my in-laws computer in the 'states and don't have access to my cut and paste file.
The bottom line on electronics is this: Look on the little metal plate by the cord and see if it will accept 220 volt 50hz power. If not, you may be able to use a converter. If it accepts only 60hz power, you will not be able to use it with 50hz, it will smoke the IC's. If it uses an electric motor, it will turn slower. The answer to most of your electronics questions can be answered by looking at the plate by the cord.
DVDs - US uses region 1. You can get a single region machine re-chipped fairly cheaply to a multi-region chip.
TV - Two broadcasting systems, NTSC and PAL. US uses one, Singapore the other. Unless your TV is multi-system (which are pretty uncommon in the US) leave it at home. Come buy a multi-region, dual voltage set here and forget worrying about it.