Aaron, If you are looking for a lightweight backpacking tent that also has enough room to use comfortably while car camping take a hard look at Henry Shires’ Tarptent Double Rainbow:
http://www.tarptent.com/doublerainbow.html
The shelter has a cult following over at backpackinglight.com given Henry’s well built shelters and excellent customer service. Right now all his shelters are 20% off. It has plenty of ventilation, which decreases condensation. The design is very stable in strong winds and provides plenty of interior space – all in a 2.5 pound shelter.
Another good choice is Ron Moak’s Six Moon Designs Lunar Duo:
http://www.sixmoondesigns.com/shop/shopexd.asp?id=47
All the same compliments above apply to this shelter. Ron and Henry are the industry leaders in lightweight shelter design.