I like Tim's use of every day household items for gear, especially the plastic bag rain cover. It's light, compact and best of all for my budget cheap. He has a lot of useful little tips for trimming down the amount of stuff you bring and ways to organize, which I like because as a backpacker I can understand the need for trimming down weight and keeping things simple and efficient.
I have gathered a whole wardrobe of clothing for hiking, backpacking and ice climbing over the years which will work well for photography in any season. I like how straight forward he is about cold weather, it can kill you. You need to be prepared for any outing in cold weather. Having a waterproof and windproof shell is invaluable. My Arcteryx shell is my favorite piece of gear. I climbed up a frozen waterfall that was dripping icy cold water on me throughout the climb. I came down coated in ice, but I was dry and comfortable underneath thanks to my shell.
One can not underestimate the need for wicking and warm base layers like capilene during the winter months either, having wicking clothing is great so long as, like Tim says, you vent properly. Wicking material is pointless if you trap that moisture in under your outer shell. I don't recommend forgoing the shell but like he suggests get one with armpit vents. Venting and regulating your temperature in these cold conditions is not just a good idea but can save your life. If you start feeling too warm remove a layer if you have to or take a moment to rest so you don't overheat. Hypothermia is a very real threat if you start sweating heavily while hiking and stop for a moment to shoot some photos or rest.
My camera takes lithium ion batteries and I always bring two in cold weather. It is vital that you do, with one kept next to your body for warmth. You will learn quickly that batteries are not made for extreme cold. I wasn't outside for more than a half hour before my camera said my battery was dead on an ice climbing trip, but if you just continue to swap the warm one with the cold one you can continue on. Something I didn't know but was glad to learn was the advise to bring a trash bag to put your camera equipment in to prevent moisture damage from condensation.
I think the winter months are a great time to take photos the light and dark contrasts are great and snow and ice can make for very dramatic photos.
His chapter "Nature Photography's Year" was a good reference for when to visit certain places throughout the year, if you have the time, money and vacation time to do so.