The answers are:
1. Running Shoes - if you have a good pair of running shoes, you can outmaneuver and outpace your opponent. It's hard to do much of anything if you're feet hurt, so make sure your shoes fit right and offer support.
2. Duct Tape - what can't this do? In addition to using it in a myriad of ways, it can be used as body armor. Wrap this around your exposed limbs to protect yourself from bites. Just make sure to attach it to your clothes. It'll take your skin off if applied directly.
3. Backpack - a good way to store and carry all your supplies. It would make moving from one place to another more convenient.
4. Pocket Knife - while it seems that this should be higher on the list because it's a weapon, it's not a very effective weapon. You would have to get awfully close to a zombie to make this effective, increasing your chance of getting bit. It could be helpful in sharpening sticks into weapons, but the other items on this list are more helpful in ensuring survival than this one.