I generally prefer backpacking type gear. I backpacked before I did overlanding, and I find some car camping gear absurdly inefficient. Besides, I simply don't have room for it at the moment since I travel with four people, sometimes more, and a big dog. If I was going solo or with just my wife and I, I suppose I could load some bulky gear. I appreciate things that make setup and teardown quick and easy. I've done trips in several different rented RV's, and I can appreciate how having some things ready to go is better than having to unpack and setup. Still, I think we can easily over-do it and get caught up with gear.
If you look at this page, about a quarter of the way down is a three minute video tour of Gunther Holtorf's camping arrangement:
http://www.bbc.com/news/special/2014/newsspec_8703/index.html
As a backpacker, I consider myself "ultralight." I am not extreme ultralight because I have responsibility for other people. I see car camping and overlanding more like heavy-weight backpacking than just an indulgence in gear like some kind of offroad RV'ing.
I like our Teton Sports -25F XL sleeping bags. They're bulky and heavy, but they're comfortable even in cold temperatures. They're definitely warmer than my 0 degree down bag was (retired after many years) and they're much more spacious. They also cost a fraction by comparison. There are better bags, and I will have to replace these for something smaller and lighter next year when my kids will be ready to start carrying their bags, but this is after eight or nine years of good use. I will continue to use them, but even on the car, their bulk can be a problem.
I use a Guyot Designs silicone bowl to water my dog. I like that it squishes into my bag or his and it's soft (not hard or stiff).
Walkstool. I have several camping chairs including quad and deck chair types, but I just don't think they're worth the bulk. I'm not much of a chair person, but sometimes you need to sit and there isn't a tree or rock. The Walkstool is all I need. Some people will miss a backrest.
For cooking, I like the MSR Reactor. There are a variety of different stoves that work well. I like the MSR brand and also have a Whisperlite International that is smaller and more versatile but slower and less convenient. For car camping, I would also consider a simple propane burner and refillable bottle. What I don't like are bulky stoves and grills.
I would consider camping in the car but I have car seats installed, and too many people to fit. Therefore I sleep outside or use a tent. I like the Eureka Outfitter series tents. These tents are heavy, but tough and they stand up to the conditions when you really need a tent. They are too heavy for backpacking, but lightweight tents are often too fragile or expensive for frequent car camping. The canvas tents are tough, but too bulky even for car camping. I would consider them if I expected to have a tent up for many weeks at a time. I am more likely to have my tent up only a few days before I move on. The nylon Outfitter series works great for this.
The right clothes actually make the biggest difference of all things.
