I haven't read through the rest of the replies, so I apologize if this is redundant... however I wanted to share my car camping experience.
In 2006 I went with one of my best girlfriends and we ended up just sleeping in our rented SUV. It was fine and we had a blast! Granted, our camp was rather pathetic looking... just a dusty SUV with a few solar lights staked around it (half of which broke my mid-week, so we looked even more pathetic!)
Bottom line: car camping is definitely do-able!
A few things to keep in mind: It is close-quarters, so you better know and love your camp mate! Also be VERY organized! Two people and a carful of stuff can quickly become a mess. So have a place for everything -- and constantly be sure things are back in place. We hung fabric from the windows for privacy, not sure much for sun-block... as we couldn't remain in the car much past 8 or 9 or so in the morning. Luckily we made friends with our RV-neighbors, but mostly for shade we hung out at Center Camp.
That's really it. It's pretty simple... but you have enough time to look into alternatives at this point.
Burning Man: I'm over it.