Bag Advice for Comic-Con San Diego

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Hey folks -

So I'm going to Comic-Con this year for the first time and am spending two days at the convention. I want to bring my camera (Nikon D7000 w/ Grip) and am thinking of just taking one lens (probably a 17-35mm 2.8). I will also have with me on the trip (but not necessarily at the convention itself):

MacBook Pro 15"
iPad 4
iPhone
Chargers/cables for the above
2x Nikon Batteries + Charger
Lens cleaning kit
Memory card wallet
Flash? TBD

My primary gear pack now is a ThinkTank StreetWalker HardDrive. But this isn't a good walking-around-a-convention pack. I also have a Tenba Shootout messenger bag and a ThinkTank Retrospective 30. The Retrospective won't hold my laptop and I'd prefer a backpack for the amount of walking/standing I'll be doing with it.

I want something that can hold my body + lens, laptop for the flight, some snacks, bottle of water or two, and then any convention trinkets I pickup. I've been looking a the Timbuk2 Espionage backpack, it seems to fit the bill of what I'm looking for. If anyone has any other options I'd be glad to hear it