Generally speaking, any laptop with an Intel Ivy Bridge Core i3/i5 CPU or AMD Trinity APU should do. Streaming video is not very demanding on the CPU or graphics core.
Your primary limitation will be your internet service. It must be able to download fast enough so that video does not stutter. I think the generally recommended minimum download speed for HD Video streaming is 15mbps or 20mbps.
There is a laptop FAQ thread that you should fill out so that people can help you find a suitable laptop.