-HK416, never fired the specific model, but I hear it is pretty much identical to the AR-15 except much more reliable. That is good because I have used the AR-15, but don't trust it for long term reliability, especially with little/no time for cleaning or reliable supplies to do so. It is also great because it is accurate enough for "headshot only" zombies, and the 5.56 bullet does enough damage to kill the "28 days later" zombie.
-Titanium Crowbar, lighter than it's steel counterpart and very useful. It is an excellent bludgeoning weapon and has many practical uses.
-Glock 17, it is one of the most rugged pistols out there, I have more experience with it than any other firearm, its quite accurate, fires a common round, and has a massive 17 round magazine standard. The Glock is compatible with even a 32 round magazine.