If you plan on storing movies on your Hard Drive, get something like Core i7 920, 2 GB of RAM, a massive Hard Drive, and Windows 7 RC1 when it's out.
If you plan on running these off the DVD, get a Blu-Ray drive, Intel Core 2 Duo, 1 GB of RAM, a decent Hard Drive, and Windows 7 RC1.
Either way, you'll want something like the ATi Radeon 3850, 500 W PSU, and a functional keyboard and mouse.
EDIT: Although the specs look crappy, they are not. It's just that much more than this stuff could be overkill if you go too far. And expensive.