I can't comment on the GPS since I've never used one. But so far I haven't found a reason that I need one, might be fun to play around with, but then it's just extra stuff to carry also.
Boots - I love my Meindl's. I use 3 different pairs. I've got the Perfect Hikers just for everyday and easy hiking. Then I switch to the Denali's when I need more ankle support like for backpacking or sheep hunting, and the Perfect Hunters for when the temperature drops. All three of these boots were easy to break in. Just throw 'em on and wear them around for a couple days and you're good to go. I know some guys who have the Alaskans and said they were harder to break in like KB said. I used to be a diehard Danner guy, but their quality has dropped a lot - they shipped most of their lines overseas. I stay away from them now.
Rangefinders - can't go wrong with the Leica 1200's or 900's if you don't need the extra distance. If you're looking to save some money, I'd go with the Leupold RX 2's. Or save up until you can get the Leica Geovids - I have a pair and wouldn't trade them for anything.
Sleeping bags - like KB said, depends on what you're using it for. For backpacking, I use a GoLite Adrenaline 20 degree bag. The only other top end brand I have used is North Face. The GoLite is better all-around IMO. The same temp bag is lighter, warmer, and doesn't lose a lot of down like my North Face did. It's also about $100 cheaper, but still around $300. It's also got the zipper on top - I wasn't sure I'd like it when I got it, but I don't think I'll ever go back to a side zipper - it's a lot more comfortable and easier to maneuver in the bag to get to the zipper. I used this bag on late sheep hunts in mid-October - it was cold, but I slept warm in long underwear.
The bag I use for going to camp is a Cabela's Alaskan Guide -20 bag. When you don't have to worry about the weight as much, it's nice to have the super warm bag and I can sleep comfortable in my boxers - I don't like sleeping with extra layers on. It's a great bag. Also nice to have a larger bag at camp so I can move around when I sleep - mummy bags for backpacking only!!!
Another thing to consider if you are going to backpack and sleep on the ground - don't overlook a good pad!!! IMHO, it's more important than the sleeping bag. I use a Thermarest Prolite 4 - nice and thick to insulate better, and super lite and packs small. I used the Exped Downmat for a week - it was BY FAR the warmest and most comfortable pad I have used, also not much heavier than the Thermarest. The problem I had was mine sprung a leak midway through a hunt and I would be right on the ground halfway through the night - it could have just been bad luck - I might try one again down the road sometime.
I can do a whole other post on just backpacking gear - I think I might finally have the setup I want for awhile after trying lots of different gear out. Although I might have to trade in the old Swarovski scope when the new lightweight magnesium ones come out. These companies need to stop making new stuff, cuz I'm the biggest gear junkie around.

Backpacks - For day packs, I like the fanny style pack that rides on your hips more than a conventional back pack. I've used an inexpensive one that Cabela's makes that is really nice. But now I have a Nimrod pack - it's great - 2 packs in one - the waist belt is a small pack that I use alone for cat hunting when I don't carry much. Then I clip on the "main" pack for fall hunts when I need to carry more gear. They also have lots of accessories like the gun scabbard - which is a must. They are super quiet fleece packs and have great padding. If you like the regular style backpack, you can't go wrong with Badlands. I've never used other brands so I can't comment. As far as backpacking for sheep hunting or bivy hunting, if you can afford it, get a Barney's pack. There is none better or even close to matching. If your budget is limited, Cabela's frame pack is nice, I used it before I got my Barney's.
I agree with KB on the kangaroo hat, and I agree with Tina on the Stormy Kromer caps - they are great when the weather gets too cold to wear my cowboy hat. Then I have a fleece stocking cap in my pack at all times in case it gets really really cold, and I just pull it over the top of the Stormy Kromer.