Your eight bucks a month will now be counted out in shillings as tons of BBC shows have just appeared on Hulu Plus thanks to a big handshake between the two companies. This means you can watch as much Doctor Who as you want, so long as it's the new Doctor Who everyone likes and not the old Doctor Who few really bother with.
On top of that, you can see other programmes like Luther and Sherlock, Top Gear, Torchwood, and a bunch of other shows that I'm pretty sure are also available on Netflix Instant.
As far as I can tell, and I cannot tell very far at all, the big deal here will likely involve the faster availability of new episodes. Eventually though, tons of stuff will show up from BBC's storied history. This should firmly identify Hulu as the ideal place to go for all your BBC needs. Future children will never know there was any other place to see such things.