Final results: Germany won again. California (beautiful architecture winner) and Illinois (gable house, passive house, American vernacular barn-like) rounded out the top three.
Personally, I really liked the houses by Penn State and Minnesota.
Penn State's house featured a row of glass doors along the length of the living space. A water reservoir below the living/dining/kitchen room helped maintain radiant heat despite the cold rainy day, and the living wall in the kitchen contained all the herbs a budding gardener could want for cooking. The deck (of most of the solar houses, actually) included a space for a small kitchen gardening - the ones I saw seemed to follow the square foot gardening method.
The first thing I noticed about Minnesota's entry was its height, and the steel frame - kudos to their civil engineering students for employing visible structure. I imagine the steep roof slope was designed to encourage northern snowfalls to slide off the solar panels, but it also resulted in a cozy alpine feel on the inside of the home. Sleeping nook, bathroom, and closets were nestled along one long side, with a living/dining great space that merged into the end kitchen with large windows overlooking a picnic table and potting area under the roof peak. I could totally live in that house.
Since the entries were limited to 800 square feet, students had to get creative with storage options. Murphy beds were very popular (I heard that under-floor beds were the norm last time). Germany's house had a few twin beds that slid out from a raised floor, and the attached stair steps hinged open to reveal hidden drawers. The Ohio team built its entertainment center into a pullout drawer on one living room wall that stored a futon, dining chairs, and tabletops.
The southern entries tended to feature a breezeway separating living area from kitchen - some of these layouts were set up to transform into one large enclosed space in winter. Iowa used a stacking glass door system to enclose a south-facing sunroom that could be completely opened in summertime.
I wish I'd had time to tour California, Cornell, and Virginia Tech, but the mall was crowded despite the cold rain and mud, so I was happy to keep the day short!
Read consumer information provided from the DOE at this event here http://www.solardecathlon.org/for_consumers.cfm
Link to my photos on Flickr.