roku has the most channels, if you don't have cable get a password from a friend.

you can cast videos from any tablet/smart phone or universal plug and play your personal collection over the network from any computer/server. play movies off a thumb drive.

the roku app is great, can be your remote when you can't find it and cast photos from your phone. play sound through headphones attached to your remote or phone. you can do voice search if you get the more expensive ones.