Zombies are coming!!!!

Shotguns are one each, pump and semi-auto.  Properly held to the shoulder, impact is negligible.

A good machete could cut through a lot... but as Rob said, why why why do you want to get that close.  With an axe, it's the head that's doing the work, so you have the length of the haft to add to your reach.  Plus the haft could be used for parrying those grasping hands that wanna grab you.

I can only echo Rob's comment on the shotgun stuff.  As for ammo, yeah... cartridged 9 mm, 5.56 mm, and 7.62 mm are pretty popular nowadays that they should be easy to get.

An idea came to me as I was looking over house boat designs (as I plan on being on the water when WWZ comes)... and I was seeing if I could mount a water cannon on my ship.  For when I come close to shore or when I see an infested dock, covered in zombies... simply dip a feed hose into the water and let the pump rip.  A high-powered firehose could knock down those zombies off the pier or where ever I'm aiming.  Same principle that fireboats used for ship fires.

I've been also rewatching Resident Evil: Extinction and seeing how the caravan idea plays out.  So far it's no good, but being on the move and not stationary could have it's benefits.  I'm also checking to see what those folks did right/wrong and wondering about what I should do IF I have to move to someplace (say far north or south to polar regions).

50 cal .. weapon is too big and heavy. as is carrying a sufficient supply of amunition.

again using the axe as a weapon.. its too slow fr what one would probably be doing. remember they wont be standing there lined up for you to take your time and aim. it will be like going though a bamboo forrest where the bamboo is clawing and grabbing at you trying to bite/eat you. quicker strikes are more effective.. again like hacking through jungle/bamboo forest. now if you can swing a fire axe as often, as fast and for as long as i can swing a machette more power to ya. but i doubt that would happen.

not everyone can get their hands on top of the line millitary assault weapons.
one should be so lucky to come across a gun dealership that hasnt allready been over run & ransacked.. likewise for police stations and millitary bases

as for RE, extinction. they did fairly well remember it was a movie and there was "plot" that got in the way such as the whole crows that eat zombie flesh and then become evil themselves.. highly dubious.. also super zombies.. possible but not plausible let alone ikely. one thing they did get right was the "once ur bitten you have 24 hours to get better or die heroically or im shooting you in the face" dealie.

again for firearms i advise shotgun, and rifle. I'd prefer M1-garande but that's just me. one of the ultra light ak-47's would do well.  and if you are going hand gun.. snub nose 357 mag or the colt 1911 .45 cal automatic. while amunition is "less available" the benefits of the weapons reliability FAR outweigh the (arguable) diffrence in availability of amunition. remember a 5.56 or a 2.23 or a 9mm dont back enough kinetic punch to knock somene to the ground.. let alone knock down a being who has no pain reflex. and we all like to think we are wild bill hicock. but hitting a moving target let alone an aimed shot on a moving target is VERY difficult.. regardless of how fast or slow the target is moving... UNLESS you are a trained professional.. millitary sharpshooter. SWAT.. avid hunter or firearm enthusiast.  the reason automatic fire and semi automatic fire weapons were invented were to put more lead down field to increase the chance to hit by less trained troops.

in refrence to "why would you let yourself get into that close quarters combat with them" because sometimes you run out of ammo and sometimes they surround you and you cant shoot fast enough. 

and getting back to things weighing too much;. many (some might argue the majority) of casualties of the normandy landings were due to soldiers being weighed down and over encumbered by too much gear that was too heavy to allow them to move let alone actualy swim to the shore. being weighed down is a REAL concern.. especialy if you are in a run for your life survival situation.
the more ammo u carry and the heavier your firearm.. the less food and water u can carry. the heavier your gear the slower u can move both in and out of combat.

AK-47s have horrible accuracy past 100 meters.  The 1911 .45, though accurate, has a limited magazine.

Can zombies climb trees or use saws?

Slow moving, supernatural zombies (ie the head shot kind) cannot climb trees or use saws.  However, they have supernatural strength or at least strength in numbers, so enough of them can attempt to push a tree over.

The fast moving, scientific pathogen types maybe able to climb trees, but not use saws.  Also those may have numbers on their side to do some heavy tree pushing.

Some folks have though of using the tree fort idea to survive the zombie apocalypse.  The book states that while hiding in a tree short term, or taking an elevated snipers position is ok... long term wise, enough zombies could gather at the bottom, and bowl the tree over with shear numbers.  Or if enough dead bodies are piling up at the bottom, they might climb up the dead bodies to reach up.

Another idea was using an offshore platform.  Since zombies cannot swim (or at the least, not travel through water well), an offshore platform would be a great place to hold up during WWZ.

My thought on trees was as a safe haven, if caught away from home where I reside.  Climb a tree with a shotgun and pistol and unless there are tons of them, I could hold out until they went elsewhere, unless it was dead winter.

Could snipe from the second floor windows just fine when they got close.  From three directions I have between 60 and 300 yards of open space.  Its that pesky north that is only a few dozen yards.  I'd be willing to lose the evergreen windbreak, though.