I have the Logitech Revue
I know you said you were more interested in the Xbox than the Logitech Revue since you have read some bad reviews on the it but I wanted to give you some info on my experience with it.
I personally use it to stream Pandora while I surf the web ever since my laptop stopped working. I like that I can keep Pandora on while I check my bank account and Facebook.
My boyfriend and I both like the YouTube app; I was glad to have it when I stayed home sick from work. Have you seen Remi Gaillard's videos? I spent quite a bit of time on the couch watching those. Boyfriend also plays the guitar and likes being able to pull up guitar tabs on the TV so he can play and read at the same time; it's looks much less painful than trying to play from a laptop or desktop. We also use it to stream movies and shows via the Netflix app almost every night and have only had problems a handful of times.