Any specifics? If your main concern is rendering, you may want to get an i7-9xx series or a much cheaper and stronger Phenom II X6. This is mainly all you need if the bulk of what you do is rendering with things like x264 and aviSynth. However, if you're using stuff like Premiere or After Effects, throwing in a bunch of ram is going to help. If you're going to use CS5 a good nVidia card can actually give you some previewing benefit, as CS5's live preview engine is CUDA accelerated. Alternatively, if you do FFT noise reduction with AVISynth, you can also get a CUDA accelerated version of that plugin and an nVidia GPU could help out there too.
Without at least a bit more info of what you actually want to do "Video Editing" is pretty vague, and can range from anything like, get a really highly core'd CPU to needing a really strong CPU, lots of RAM, and a decent CUDA GPU.