Simple Basic HTPC setup (1 Viewer)

Hi, I am going to be ditching my cable and I was hoping to find a low-energy HTPC setup that would fulfill my needs. The first priority are for my visual media needs, which includes hulu free, youtube, any/all network websites, and netflix, most likely at standard resolution, but HD would be a nice addition. My second priority is to have this same system be able to do music, such as pandora and itunes or something. Right now, it seems there is no set-top box that would fulfill my visual media needs or my visual/audio needs. So what's the most basic system out there, for purchase or for building, that would fulfill my needs and have low energy consumption? What would the basic components look like? I keep thinking how a perfect system would have something like a Iphone interface, with only the audio and visual apps(pandora, hulu, safari, etc), is there anything like that out there? Thanks for your help!

For what you're after, which seems like some TV viewing (so TV tuner, but OTA and online) you might be well off looking at a little ION or Zacate box.. you can get together an entire system based around either for sub-$300.