In terms of streaming (I have the unlimited dvd (1 out at a time) and streaming; I should also mention that I will cancel Netflix as they increased their prices), my Netflix account recognizes all my computers as a single device. In other words, my family of 5 have a computer each and even though Netflix should show 5 devices (excluding iPhones and iPads), it only shows 1 (which is cool I guess).
Anyways, like I mentioned above and someone else corrected me as well - even though it is based on personal preference, I do not see myself paying $7.99 just for their online content. IMO, Amazon has better titles in terms of streaming only and I get that for only $40/YR (which is much cheaper). I get it for only 40 and not 80 because according to their email I am a long time customer so I get discounted pricing (not sure why but great I guess).