You need the following:

A detailed Map
GPS unit
Preferred sidearm/firearm
Water
some food - whatever you want to carry

JIC you get lost...

Sweetwater Water Filter Pump
1 - 1L Nalgene Water Bottle
A couple energy bars (just in case)
emergency blanket

More likely than not, you will not use your knife in the woods during day hikes, unless you want to just screw around and chop stuff up and take pictures...