Fixing the bugs before new features is always more important. :up:
I currently have 5 dropdown fields and 3 text fields. The dropdown fields are pretty straight-forward as only one selection per field is possible (like bodystyle, transmission etc.)
I also have 3 text fields. Two of these are actually number fields (mileage and model year) and search for a range would be awesome. For example, search for cars between 2003 and 2006 model years or cars between 0 and 30K miles. Pretty much the same as it is currently set up to search for a price range.
Example of vehicle with all extra fields:
http://saabworld.net/classifieds-5&urlid=2/