I'm so careful about what my DCs watch that we don't even own a tv! Or have any computer games or a wii (nor do we let them watch the adult news on iplayer) ..
In fact watch hardly any films, DD decided Dawn Treader would be too scary for her a couple of years ago and we didn't take them to Christmas Carol either as trailer looked nightmare-inducing. We vet Merlin episodes before they watch them. Totally avoid realistic violence and I'm as judgy as some of the posters on here, especially about innocent vulnerable small children being exposed to awful adult films.. but as ours are big fantasy and LoTR fans we took them to Hobbit today (DS is 6) and they both hugely enjoyed.
We got there early to ensure aisle seat in case of needing to pee, both parents prepared to take them out if not enjoying, no rustling sweet wrappers or mobile phones and strict instructions to whisper in the slientest voice if they wanted clarification.
It's a children's book that the whole family is really into and we've discussed it loads. DD is having a 'one ring' birthday party next month.
How is that irresponsible or selfish parenting? It was right for all of us and didn't disturb a soul in the almost empty cinema.
As has already been said, The Hobbit violence is clearly far removed from real life, mainly goblins getting pushed off bridges. Battles scenes are free from gore and when the city of Dale is burnt by the dragon it's kites and a kid's doll that you see on fire. There're lots of glorious sweeping scenery shots and themes of belonging, homes, mercy, courage and loyalty. For us the only possibly scary part was the Necromancer's fortress but that was framed by Radagast the Brown (crazy nature wizard) riding his sleigh pulled by rabbits and nursing a hedgehog called Sebastian back to health - thought we'd wanadered into a Disney film at that point.
The most disturbing thing for our DCs were the adverts and trailers beforehand.