In my office:

My 24" Dell LCD monitor has component inputs as does the older HP monitor it replaced. Also has S-Video, DVI (2), VGA. Some newer LCDs have HDMI as well.

My 52" Samsung LCD TV has 4 HDMI, 1 VGA, 2 Component inputs.

I can use either for TV. My main PC is running Vista Ultimate and has a TV tuner and Media Center. I use the 52" as a secondary monitor too.

Make sure if you're getting a monitor that is HDMI that it is 1.3 compatible. This offers content protection and is required for some types of output (example: Blu-Ray from a PC ( not available on Mac :p )).

BTW, the newer 24" Apple monitors only have one input (mini DisplayPort). WTF were they thinking?