What software do you use? A look at the equipment specifications will give an idea of what you require.
If you're planning on HD editing then an integrated graphics card won't be enough and a high(ish) end card would be required.
A quad core processor would be beneficial but only if the software is multi-core aware.
Fast, large and dedicated hard disks would also be of help e.g. a disk for the OS and programs and at least one other for the actual file prrocessing. The 1TB Samsung F1's are getting great reviews for performance.