Top of my list would be a good pair of boots that work with your feet, if your feet aren't happy, you won't be.
I'll second this. Your feet are critical to having fun and getting out alive. As others have said, don't cheap out, you may depend on this stuff to keep you alive. Backpacking is much simpler than backpack hunting; what the heck is a trail? I'm almost always solo so I can't split the load with someone else. I went up scouting Friday and came out late last night, a good headlamp pays dividends. Where I live water is always an issue, there may or may not be water at the bottom of the canyon but that's 800-1500 feet below and I can't glass/hunt from down there, so I cache water.
Here's my simple list of the common stuff I took this weekend:
tent - golite Shangri-La 1 (didn't use it but it was with me); on day trips I have a piece of Tyvek with me
bag - hyperlamina spark if not too cold otherwise it's an ultralamina (it's about 1.5 lbs and I'm irrationally worried about down getting wet and we can have 4-seasons in a day)
pad - klymit inertia
jetboil - and starbucks via...mmm hot coffee in the AM
steripen - always with me, day trip or longer
headlamp - princeton tec remix & zebralight floody (I don't want to get caught without a light)
raingear - even in summer
gators - kenetrek; always with me
boots - Asolo
sock liners - bridgedale coolmax; always taking care of the feet
fingerless ragwool gloves - warm when wet, trigger finger is accessible, protect my hands...priceless
pants - pacific trail cargo; I'll be ordering more of these, they stretch which is awesome and burrs (porcupine eggs, cheatgrass and other stuff) don't stick to them like the others I've been using this summer.
trekking poles - black diamond carbon elliptical; I never go out without them and when you're packing your animal out they're priceless. It's like a 2WD vehicle vs a 4WD vehicle.
satellite tracker/communicator - since I'm solo most of the time, if something goes wrong I could use my cell to take a last pic but there'll never be service where I am. I've been using a SPOT but I just ordered (this AM) a Garmin InReach Explorer+ so I can text back and forth with my wife and she can follow my trail with an app.
solar charger; not critical but I've come to depend on mine to recharge my phone
baby wipes in a ziplock bag - thank me later
gold bond powder - just a small pill bottle
first aid/emergency stuff - parachute cord, superglue, lighter, needle, floss (for thread), antihistamines, ibuprofen, eyedrops, moleskin, bandaids...
spotting scope
binoculars