Hmm... I'll see what I can come up with. I'll go with current models and very recent models (built within 2 years) to simplify things. Otherwise the Worst list would include a lot more models.
Top 10 Best
1. Acura TL
2. Mazda 3
3. Lexus IS
4. Acura TSX
5. Infiniti G35 Coupe (previous version. haven't looked at the current one yet.)
6. Infiniti M35/45
7. Mitsubishi Eclipse
Hmm, running out of ideas... Oh, you didn't specify Japanese.
8. Hyundai Sonata
Okay. I'm not a fan of the following designs, but I need to finish my list.
9. Nissan 350Z
10. Scion tC
Top 10 Worst
This is much easier, though difficult to put in proper order. The following is an approximation.
1. Scion xA
2. Toyota Prius
3. Honda Ridgeline
4. Toyota Yaris (Sedan and Hatch get to have a tie)
5. Honda Element
6. Scion xB
7. Nissan Titan/Armada
8. Toyota Avalon
9. Nissan Quest
10. Nissan Versa Sedan
Honorable mentions...
Toyota FJ Cruiser
Honda Civic Sedan
Toyota Camry
Isuzu Ascender
Mitsubishi Diamante (in its last iteration)
Edit: Changes...
- Forgot about pick-up trucks. Nissan Armada/Titan slips in at #7. Honda Ridgeline at #3.
- I decided that the xA is in fact the worst looking car in the US. Forgot about it previously, because they're not all that common.
- On second thought, the pre-bodycolor Element is uglier than the xB, and will continue to taint the appearance of our roads for years to come. They swap positions.
- I decided I like the Eclipse better than the Sonata (also, just picked one up in NFS:Most Wanted, and it's quite the contender). They swap positions.
- The Lexus IS looks pretty good, but I think I prefer the TSX. They swap positions.
- The models that were knocked off the Worst list still get an honorable mention. Also added a couple more chokers to that list.
- I've expanded the list to include recently built models, as there are a few on this list that may have gone out of production.