Okay, I've given this some thought.
If I were in a zombie apocalypse and I can pick 3 characters, real or fictional, to bring as sidekicks these would be my choices:
Autobot Hoist (Toyota Hilux tow-truck ver.) - Hoist is a good choice because in vehicle mode he offers moderate off-roading capability, is indestructible, can tow away epic loot and consumes no gasoline. He is also an expert on mechanical repair and can transform into a robot. Robots have a favourable matchup vs zombies because they have no brains and are made of metal.
Hayate Yagami (Force ver.) - Having a magical girl around is like the ultimate swiss army knife isn't it? Plus, having a healer is probably important in a post-apocalyptic landscape. I had also considered Hermione Granger, but felt that her load of useless art courses and clear inferiority in offensive magics would lessen her utility by comparison. <_<
Kirby (ice+spark) - I just really like the idea of having a refrigerator full of food around at all times.