I've got UnblockUS for US Netflix, and it gets past the region-blocking on HBO, etc.
Also works for my UK iTunes account, which I just created.
In the UK store, the Now TV app is a premium content package (and expensive), I've got a free 14-day trial (signed up with my Canadian credit card and the postal code of a pizza joint in London). Don't know if I'll keep it, but it looks like there's some good stuff on there.
But the standout is the UK "TVPlayer" app, which streams live TV for 30 or so 'basic cable' channels (all the BBC channels, food network, Discovery, etc). It's completely free, and streams flawless HD. Apparently this is just a standard service for the UK. Nice when you aren't saddled with a cable-company oligarchy.