You can get some really cool wall plates at Home Depot as well. When I finished my basement this fall I went with the "keystone" variety. Here's a
link to what they look like. Really flexible system. They're in the electrical dept.
I've done a full 5.1 sound system with rear speaker jacks in the ceiling, and run composite, s-video, RGB component and RGBHV BNC component, DVI, and HDMI behind where the big TV will go someday.
Now I just have to save up for the TV... B)