You want to be able to read large files serially very fast - so a computer with a large fast disk that spins quickly and gives a rapid serial transfer rate would be good. It also needs a reasonable amount of memory, and a fast CPU with dual or quad core. You also need a speedy graphics processing unit. Video takes a lot of space so you will also need an easy way to back up to tape if you do a lot of it. It's easy to fill a 1TB drive with video data. Minimum 500W power supply -- good quality.
You could also use a colour monitor that is designed for artwork so it will display the colours correctly.
Your best bet is to search for turnkey NLE solutions (NLE stands for Non Linear Editing), turnkey means that it's custom designed and ready to go upon purchase.
Go to bit.ly/JY1pQn for example and get much more detail.