One option to look out for is TiVO. It handles Netflix, Amazon, Pandora, and with a service running on the PC that holds your media - any format.
TiVO supporters laud its simple UI, very effective searching, excellent remote, and overall outstanding experience. Wife acceptance factor is very high. It's detractors point out its cost.
Unfortunately there is a monthly cost for TiVO of $9.99 (for OTA only) or $13.99 for cable TV. DirecTV or any of the IPTV (Uverse/FIOS) not supported.
It currentlly isn't possible to not pay that fee and still get the streaming aspects.
Also note that its a little less "streamy" than you might think. Netflix streams just like the website, but Amazon VOD starts a transfer, which you can immediately begin watching. Its possible to catch up and pause. Same goes for stuff on the network.
We just reactivated TiVO that was purchased 2 years back ($199 I think) and upgraded HD to 1TB - they offered $99 lifetime guide data for resubscribing so I bought. I had paid full price for roughly a year and had deactivated for a year.
Total price then was about $450ish.
Nice to know I can go back to Comcast without having to use one of their boxes (though of course you don't get the stupid comcast on demand BS).
Also its an Excellent OTA tuner (which is what it is doing now) - inside antenna - 1st floor of 2 floor apt in deep suburbia - roughly 25miles from transmitters in either direction, and I can get both markets basically.