You NEED a shotgun. They're probably the most common type of firearm, usually relatively simple, and increase the chances of a headshot, which is especially important if you aren't a marksman.
Tasers (the type that fire darts) could be invaluable, so long as the zombies are still dependent on electrical impulses to control their muscles.
Gasoline and other flammable materials aren't exactly useful, except as fuel, since most zombies are impervious to pain, and don't seem to have any sort of need to keep their temperature at a certain level. The only reason you might use them as a weapon is if the zombies depend on oxygen, which a flame would quickly deprive them of.
MRE's are always a good idea: they include many useful items, and are practically indestructible.
A clean source of water will be invaluable, if the Z-virus turns out to be waterborne. Thank goodness for the inventor of bottled water.
Constant vigilance is impossible, so it is vital that you find at least one person to watch your back when you're asleep. If you do form a group of more than two people, however, a clear chain of command is vital.
Zombies tend to be rather sneaky, for no particular reason, so a system of detection will be vital. Still, do not depend on it exclusively- doing so will dull your senses and leave you vulnerable.
EDIT: Cthulhu, you don't know if the zombies can swim. And if they don't need to breath, they could sneak up on your boat, completely submerged. Not cool.