This sounds sooooo awesome! First off, it takes really twinky Brits to make an insult like "drink-sodden former Trotskyist popinjay" sound offensive, but there you are.
I think both these guys are dickwads: Hitchens is an arrogant, name-dropping twit who, while undeniably hyperintelligent, is also a judgmental intolerant prick who's regard for George Orwell (well-placed regard; Hitchens' book Why Orwell Matters is quite awesome) is surpassed only by his regard for Christopher Hitchens.
George Galloway, on the other hand, is absolutely reprehensible. Although adopted as an iconoclastic icon of resistance by the left because of his outspoken resistance to the Iraqi war, this perception of him has to be taken in isolation, because in just about every other facet of his life and personality, George Galloway is a scumbag. His only regret in life is that Stalin died to early for Galloway to be a proper Stalinist. An apologist for Saddam Hussein and Islamo-fascism (note that I'm not conflating the two; Galloway basically likes any flavor that's anti-Western), he was knee-deep in nefarious dealings with various people of a less-than-savory reputation. It's been hard to make any of these charges stick, but I certainly do go by the "smoke and fire" tenet (note that the little prick can't sue me for saying that).
I guess I'd probably choose Hitch on the basis of his relative lack of involvement with horrible people. I'd predict that he'd win because Galloway is primarily a demagogue with a very slippery grip on facts. But in the end what I really hope to see is a good fight, with a few sound bites that can measure up to "drink-sodden former Trotskyist popinjay."