I would recommend living in halls, had the option to live with my family in Hampstead (15 mins to UCL by tube), but ended up in Camden halls- I still have to take a bus every day, which is very annoying, but it's far more sociable. Halls often have completely spontaneous parties going on and if you live out you have to plan your free time with your uni friends, which sometimes doesn't really work out. From my experience, people on my course that live in halls are the ones that socialise most, those that live at home are less into parties- it's far, they're tired, so they can't be bothered and traveling home after a night out isn't really safe.
Of course the good thing about living at home are the home comforts, but you can always go home for a day off or a weekend and enjoy it.