2005 Nissan Altima 3.5 SE 4dr Sedan (3.5L 6cyl 5M)
I bought my 3.5 SE new in 2005. I only have 28000 miles but I have had very few problems. The car has only been in the shop for routine maintenance. However, in march of 2009 I had to replace my battery. I have heard of others with this problem. Overall I am happy. The 3.5 engine has a lot of power. This is fun at stop lights and has gotten me out of a few jams on the freeway. The complaints about the road noise (esp in the back), turning radius, and cheap interior are valid. They are not prohibitive however. I live in DC now so the turning radius is more pronounced. I have taking this car on 400 mile trips (I can get 33 mpg on the highway) and have been completely satisfied.
No doubt the engine performance. Also, the radio controls on the steering wheel. Heat and AC are very powerful in hot and cold climates.
Turning radius needs to be addressed. I read about this problem before I bought my car and dismissed it. 99% of the time you will not care but in tight parking lots it is a pain and making a U-turn can be dangerous.