I would like to hook up a PS and an Xbox directly to a tv. I am assuming I don't need any other components. Is this true? I don't care about broadcast reception, so can I just get a cheap flatscreen HD tv on a stand for $100, plug in the hdmi cable for the console and I'm all set? And what kind of tv do I need if there is something better for games?

You shouldn't need more than what comes with the consoles, unless it is an older generation of console without HDMI and you have the one TV without component inputs.

I would check what the (max) resolution for the console is, and match that with the tv.

For example, I wouldn't buy a ps4 and a tv that cannot output 1080p.

a tv with two inputs is handy aswell.