What's a good computer for streaming Netflix and YouTube?

I was just wondering because I watch a lot of media for my job and right now I have a iMac g5 and as you may know, g5 processor is kind of behind in the times, but I would like to keep my iMac. So, I'm looking for a pretty cheap solution, I do need it to be windows because I would like to run some programs that are only for windows and preferablely a laptop (even a netbook) because I already have an all-in-one. I just put Netflix and YouTube up there as examples, I would like it to stream generally popular media (I.e., crackle, Netflix). I really could not do with another computer that streams laggy videos.