Prepare to spend a ton of money. All the gear adds up fast. REI makes it super easy; you can get whatever you might need from them.
Size of pack: How long do you expect to be out? 5000 cu. in. is plenty for a weekend. If you get into week-long trips, you'll need more.
Stove: I swear by the MSR Whisperlite. Light, cheap, and almost unbreakable. They make them in a universal fuel model, too, so you can pretty much run it on anything.
Food: Don't try and cheat and go with freeze dried crap; it's expensive, tastes bad, and doesn't give you what you need. Take whatever doesn't needed to be kept cold; cheese will still work. Try to avoid cans since they take up a lot of room and are pretty heavy. As a rule of thumb, bring about 1.75 lbs of food per person per day.
Tent: Depends on your price range and how big you want it.
Clothes: Thermal layer, fleece pants, rain gear, two fleece tops, hat, gloves, the works. Don't try to save a ton of weight by saying "I am man. I not get cold." But don't pack so many layers that you can't have any food.
Bring a compass, maps, headlamp, knife, first aid kit. Don't be a dumbass.
What kind of climbing are you doing?
Sorry if this isn't the info you're looking for, hopefully this helps.