If you live in Hoboken and like it, I agree that Clapham is a nice fit. It has a similar vibe with lots of post-uni 20-somethings and young profs – and as an added plus it’s greener than Hoboken. You can find pretty much anything you want in Clapham and it has good transport links (though I agree with Britwife, it’s a hike to KingsX).
But you have to pay for those bars, restaurants and other amenities. I’m not sure where you came up with that £800 pcm figure for rent, unless it’s a share, but when I searched on
www.findaproperty.co.uk only 1 flat came up at that price.
It's Just my opinion, but I think you'll have to re-evaluate your housing budget or standards quite significantly if you want to live in Clapham or a Clapham-like area.
Balham has a less intense scene than Clapham and though it’s lovely, it isn’t cheap either (the same search produced 4 flats).
Here are some other areas you may want to explore:
West: Fulham, Hammersmith, Chiswick
North: Camden, Islington, Crouch End
East: Shoreditch, Dalston, Stoke Newington
There was a resent discussion about this very topic here:
http://talk.uk-yankee.com/index.php?topic=53151.0started by chadwyckp, who is looking for a similar type of neighbourhood as you. You may find some useful info.
Good luck