If you like an external frame pack, I like my Jansport Carson.
If you like an internal frame pack, I really like my Osprey Atmos 65.
I usually go for a week at a time, so I need the larger pack. You may not need as much room. If you live in the Bay Area, there are several REI stores where you can go to try different packs. That is by far the best thing to do.
The basic gear list is shelter (tent/tarp), sleeping gear (bag and pad), and cooking equipment (stove, pot, bowl, utensils), and water container. Add to that a few things like water filter/purificatin, first aid kit, firestarter, a change of clothes, windbreaker/jacket/raingear, toiletries (TP, toothbrush/toothpaste), sunscreen, bug spray, sunglasses, map & compass, headlamp/flashlight. A camera is nice. Anything more is a luxury. Your first time you will probably carry far more than you need, "just in case". When you get home, evaluate what you used and what you didn't. If you go on a couple trips and don't use something, don't bother carrying it any more. If there is something that you wish you had taken, bring it along the next time. Over time you will get to the point where you will take just what you need and nothing more.
If you lived around here, I could show you what I usually take.
A knife or two goes without saying on these forums.