Greens, assuming they have a local candidate. I'm a life-long Labour voter (and was a party member for several years) but I really feel they're unelectable with Miliband as leader.
I could never in good conscience vote Conservative as I fundamentally disagree with almost everything they stand for; the Lib Dems don't deserve a single vote after screwing-over students in 2010; UKIP are not a party I believe in, and I also don't believe in 'protest voting', so they won't get my vote...
So, if there's a Green candidate they'll get my vote, otherwise I'll spoil my ballot paper.