There are literally thousands of variants. When choosing look for one with good gas mileage, equipment storage and durability. Most roads ill be blocked or jammed. Imagine how your vehicle could handle crossing snow, mud, rocks, creeks. If not very well, you may want to think about another option of transportation.
In a class by itself, this vehicle offers the best of both worlds. The bike is fast, quiet, muscle-powered and easy to maintain. Add the additional advantage that is the only vehicle you can pick up and carry if terrain gets too tough and you've got a winner. For optimum performance use a mountain bike. Please don't let mobility go to your head, the bike offers the least protection of all vehicles.
Assuming either you or someone in your group has the knowledge to fly a helicopter this may seem like a great way to get around during a zombie apocalypse. Why run through the walking dead when you can fly over them? While you may like the ability flight, findind a place to land is another issue. Helicopters are loud, on a normal day you can hear one coming from miles off. Image how many walkers would heading towards your sound. Also fuel is another issue, gas for a helicopter won't be as accessible as for a car.
Fueling from a gas station becomes irrlevant. You will need horse feed, medicine and possibly a blanket. Your terrain options increase as your no longer need the road. However horses can become easily spooked by a zombie, which could present a problem if the horse bucks you off leaving your stranded and injuried.