A Few Questions

I am looking to build a pc that will enable me to first and foremost watch HD/BD movies on my sony bravia xbr tv as well as play games. One of the things that I am most adamant about is choppiness/framerate. I don't want to be watching a movie and having it skip and what not.

My budget is $1000, give or take $100 and I have a good understanding of the components I need, I just have a question about their order of importance.

I know that the mobo, cpu and vc are my 3 most important parts I'm just not sure how important each one will be to my setup. What I mean is, should I spend more for a high-end graphics card and only get a decent mobo and cpu? Should I try and keep all things even?

As an example, I do not plan to go this extreme but would it be better to get a Radeon HD 5870 or an Intel i7 920?