Depends where you live. A lot of this stuff can be acquired afterwards.

As an Aussie, firearms are very hard to come across. Also, I’ve never fired a gun before, so I would pick the shotgun because I know my terrible aim would be mitigated somewhat.

Water purifier. Duh.

Fire axe. Utility + weapon.

Tent. I live close to nature, so my game plan is to stock up on nonperishables and go camp for as long as I can, and hope that the zombies have thinned out by the time I need to start savaging