What hardware would I need to make a video montage with music on youtube?

Get a computer with a dual or quad core processor. It needs to be at least 2 GHz, but if it is in your budget, go up to 2.4 or 2.6. Choose Intel, but AMD is fine if you want to save some money. Get a DVD burner and a good graphics card. Go for ATI or NVIDIA, either are good. Go for at least 512 MB onboard memory. Your ram should be 3-4 GB. You can make a video with movie maker, so you don't need to buy any software. If you want a more professional editing environment, I use Pinnacle Studio Ultimate, and it works pretty well (~$120). You could buy Dell, HP or other major brands. Enjoy your new machine.