Power consumption is always listed on the device. The real issue if I read between the lines is keeping up with the electric demand.
Personally I have an under cabinet combination TV/DVD/CD/AM-FM radio. It uses up no counter space and the screen folds up flat. I have it hardwired into the battery banks on the boat through the switch and fuse panel.
I have two separate banks of batteries. One bank supplies the "fun" stuff like the TV, inverter and computer. The other supplies the electronics and navigation lighting. I have an alternator output on my motor that recharges the necessary items. I have a shore charger that has two outputs for both banks and a small generator too. The only time I use the generator is when I've been away from shore power too long. I often spend weeks out or at anchor. I never suffer from lack of electricity.
Pick your appliances wisely, calculate your normal usage and plan your battery banks and charging means according to that. You can't go wrong regardless of which appliances you choose. Always separate the necessary from the fun stuff. It's dangerous to be without radio, navigation equipment and navigation lights. Save plenty of battery life for those things first. You'll live if you can't watch the TV or chat with people on this forum.