I am a bit on the fence. (My actual voting behaviour is already determined, since I think my local MP, who is a Liberal, is a mensch and ought to be re-elected.)
Harper is right on Afghanistan. He probably ultimately has good impulses on economics, although I have seen scant evidence of it in the last 3 years. Arguably, the Liberals would grow government more. Certainly, there is a risk of a unionized, one-size-fits-all universal daycare program, which is immeasurably worse than Harper's baby bonus. Harper should also get credit for selling a symetrically decentralized federation to the soft nationalists in Quebec.
On the other hand, Dion's plans are actually broadly economically sound. He wants to shift taxation to negative externalities which is good both for Pigovian reasons and because the long-run elasticity of demand means it will shrink the tax take. Harper's GST cut was unwise.
Finally, the election call itself is such a cynical breach-of-promise that I can't help but hope it backfires.
But while I hope that the Liberals win a plurality, I don't expect it. My prediction is the Conservatives back with an increased plurality, based primarily on gains in Quebec, but no majority. The Liberals will collapse in Quebec, and lose some ground to the NDP in their urban Anglo strongholds.