The 2 most important items of gear for me are a good pair of boots and a good pair of binoculars.
I put the backpack as #2 and optics in the third spot depending on the hunt. That said, I've never gotten a headache glassing like some have.
An ill-fitting pack just grinds me to the ground.
Boots are an interesting topic and are very subjective. Lots of folks like stiff boots. Some like softer boots. I know a few guys that wear tennis shoes until the snow flies and they spend 4-5 months in the rough stuff. I wear a light hiker until the snow flies and then move to a Zamberlan Guide.
Jeremy