I camp a lot by car and boat, and enjoy having a comfortable setup. If you're not backpacking, you can get much cheaper, low-tech equipment.
IMO, a comfortable air mattress is the most important thing for making it a great experience. I have a Thermarest ($$) that I use when I need to travel light, but you can't beat a thick, cheap Coleman twin size air bed from Wally World for sheer cush. Unfortunately, they're not very durable, and seem to leak after a few years. You'll need some sort of pump, too.
I recently added a big LL Bean cot to my sleeping setup, and it's really nice. Not necessary, though.
For the summer, basically any sleeping bag will do. I like the big rectangular roomy ones.
Your pillow from your bed will make you feel like you're in the lap of luxury.
For tents, I have always had good luck with Eureka. Get one sized for twice the actual number of people who will be sleeping in it.
A nice big cooler.
A propane Coleman 2 burner cook stove.
Propane lantern is cool, although the fluorescent ones are pretty good. I really like the candle lantern for just a little extra light around the campfire, if you don't need bright light. Uco brand, I think?
A big bin for food and cookware.
Water and a refill plan.
Hammock is nice.
First aid kit.
Toilet paper, and a plan for going #2.
Some of my friends swear by a rain fly. We've never used one, but have thought about it for over the picnic table. Good for shade or if it's rainy.
Solar shower is really nice, if there's water and a little privacy.
Cards, board games, books.
My rules for avoiding a really shitty camping experience:
I hate camping in the rain, and it seems whenever I've talk to someone who said "I tried camping once, and hated it", it turns out they always got drenched in the rain. I will skip a camping trip rather than camp in the rain. Even your favorite people crammed in a tent for a day or two wear really thin.
Avoid noisy neighbors who want to party all night, crank their gross music, and whoop it up until dawn. Unless you are one of them and then please camp someplace far away.
Animals, especially raccoons, are a real pain. Raccoons can torture you and wipe out all your food. Hoist it high in a tree. Bears are something to be aware of and prepared for, too.
Clean dishes and cookware thoroughly to avoid food poisoning. Getting sick while camping really sucks. It's harder to do dishes while camping, but very important.