Hrm... Since the Mrs. and I are going camping tomorrow, this is pretty fresh in my mind... :) Now, all my advice is based strictly on car camping, not backpacking type adventures. :)
I second the suggestion to get a bigger tent... As well as a *good* tent... A quality 4 person tent shouldn't be too much more expensive than a quality 2 person tent. Plus, I'm not sure how tall you are, but one thing I hate is trying to change in a short tent... And I really hate finding that because my bag was pushed against the side of the tent, my bag is now very wet from the dew.... Or drenched from the rain.
Sleeping surfaces - several suggestions and routes available.... From the little Thermarest pads to something like an AeroBed... All depends on how big your tent is, how much room you want, and how much padding and thermal insulation you want between you and the ground. But being a bigger guy, as well as a side-sleeper, I like to have something more between my hips and the ground than a little thin pad.... Especially when you climb into bed that first night and find the one rock you missed when setting up the tent.....
Lights.... Have flashlights. Have *more* than enough flashlights (although I imagine that's probably not an issue). Lanterns - if you have propane or other hydrocarbon combusting lanterns, make sure you have plenty of fuel as well as spare mantles. Long matches also are nice for reaching up in there and lighting the lantern without the *FOOMP*.... Speaking of matches, either waterproof matches or keep them in a waterproof container. Also have a backup means of making fire (lighter, magnesium firestarter, something!).
Stove.... I actually really like the little red Coleman "tailgater" type stove... But I also have an adapter hose that lets me connect a 20lb propane tank as opposed to the little 1lb cylinders.... That being said, the Mrs. and I have one of the Camp Chef Explorer stoves. 2 burner, and doesn't have all the different grill/cooking surfaces as the Coleman stove, but it puts out a *lot* more BTU's. Pretty nice for when you want coffee in the morning, or hot cocoa at night...
Also gonna second the totes - we have 3 right now... One is our gear tote, that has lanterns, flashlights, air bed, pump, etc.... Another is our "kitchen" tote. It has all our kitchen stuff - including two little basins that we use for doing dishes... Third is our dry food tote... Again, pretty self explanatory. At night, almost everything from the kitchen and everything from the dry food tote goes back into said totes. Keeps fearless critters from sniffing/tearing into things.... When we're done with the trip, everything gets cleaned, checked, replaced/restocked if necessary, and then back into the tote. Then we're ready to go for the next trip. IMPORTANT NOTE: Make sure you have a can opener... In fact, two. In two different totes... :)
A good cooler is a definite must.
Tarps, rope, a small hatchet for splitting firewood into kindling, etc. We *really* like having a canopy that we can set up over our table at the campsites. Works equally well for keeping unexpected rain off stuff as keeping the sun from making things too hot... Garbage bags, also a small broom/dust pan for cleaning out said tent at the end of the trip (it's amazing how many pine needles, etc get tracked into the tent).
A good first aid kit.
Some of this stuff is "nice to have", others are really "ought to have". All depends on budget, timing, and the type of camping you're doing... If you're going with people that go camping regularly, it's nice to avoid duplication, and you can work out who has what and then bring what's needed.
