in my experience
hey, well most of what i know i've lernt it from mtv and music, watch all the shows you can, and don't get too attached to subtitles.
when it comes to music, well, it depends on how advanced is your english level, but I reccomend you to listen to this groups for their amazing lyrics, sound and great pronunciation:
-The Killers
-Death Cab for Cutie
-Red Hot Chili Peppers
-The Rasmus
-Pink
now these others are british and just like the ones above their lyrics, sound and pronunciation are excellent, and I just point the fact that these are british 'cuz you'll get to find some words are pronnounced diferent from the US/standar english, plus this will train better your listenning
-Coldplay
-Arctic Monkeys
-Robbie Williams
-Travis
Good Luck M8