Welcome to Tom's Forum!
Look for 'gaming' computers; they will be good enough for trading.
Personally, I use an i7-920 computer for my trading activities. It's fast and reliable. This one I built myself.
Laptops are not ideal for trading because of the slowness of the wireless connection. Therefore they must be hard wired to the internet. And if you are going to hard wire to the internet, why not use a desktop instead?