I've watched every mythbusters to date 
I downloaded alot and have a mixture of both the US and UK commentator.
Try Misfits, its not for everyone but has good writing. Stay away from all British soaps/reality TV, it'll put you off the British for life.
I've only watched a couple of primeval but it seemed ok as did the sanctuary(both kinda like Dr Who).
Peep show, Ideal, The Office(UK) and Scrfapheap Challenge are the only other british programmes I watch