So I want to put all (or most) of my dvd and blu-rays on my Tv so that I can just play what I want when I want. What should I use to do this, an external hard drive?
You need to rip them onto your PC/external into AVI , MKV, or what have you. You can find free apps or trials....just google DVD ripper/burner. Then dump onto your TV from the hard drive. Make sure you know what types of video files your TV can play.