What are your specs? What things do you want / need? Is it a brand new build, or have you got things you can use? (Operating System, Case?) Whats your specs?
If you have no experience in anything, it might be best first reading a few books, or maybe buying a pre built package, if you need it ASAP.
This may not be the best idea if you're new to the whole thing, but an interesting approach using something like MythTV would be to have a single, large, powerful, expensive, noisy server churning away somewhere out of sight and mind. You can then build and configure as many front ends as you like, all that use the same backend and therefore have the same resources.
This means your front ends can be:
a) linked together with the minimum of hassle
b) cheap
c) quiet
...in my mind that's the approach to take these days, especially if you'll be wanting more than one around the house. Might not suit your needs, but I thought I'd throw the idea out there in case
i wanted one were i could use as tivo, burn movies, download songs, etc? As for what mobo and cpu and video card, tv tuner, capture card ....I have know idea of what i need
Pretty sure you can. Might depend on the drive though.
When I asked where you were putting it I should have been more specific. Do you want it on the floor or in a desk somewhere, or in an entertainment center?
Basically I was wondering what kind of case you'd need, and how loud it can be.