I need to build a home theater system need advice?

Just a small word of advice for the sub. Bigger doesn't have to mean better. You can perform little tricks on your sub, depending on the model of course, that can give you deep, hard hitting b at a great price. My advice would be to find a sub that has a built in crossover as well as independent volume control. You can set the crossover to a relatively high level and direct most of the low frequency effects it's way. It's not ideal and you'll lose some clarity but hey, it'll pound. You can also tweak the volume level to help achieve the desired b. And of course, let's not forget the oldest trick in the book. Place your sub next to a wall if at all possible. It'll shake your house to it's very core. Uh, don't do this if you live in an apartment or share any common walls. It's a good way to piss off your neighbors.