HTPC setup for noob

Hello everybody. I am working on a new project which is a home theater PC. Ill probably run Media Center 2005 or maybe XP not sure yet.
Anyhow, Im confused on how to hook it some things up. So after all the hardware's put in the PC. Where do I plug the TV in? the video Card? or the TV tuner card? Initially I planned onto hooking the TV to the VGA and have the TV tuner so i can get television through my TV. but after looking at the actual tv tuner card. it also has outputs that can hook up to the tv. If thats correct how will that little card have that much power to run a TV. It makes more sense to hook it up to the VGA right?
I read the manual that came with the Tuner card and it didnt say nything about the VGA going into the TV. So now im really stuck and need some help . I apologize about this really long topic but im sorta a noob at this.