I dunno, that is a difficult one. Sticking to 2004MY cars I would have to pick the Neon SRT4, even though I don't ever see myself buying one. With the refinements made to the car since it's introduction (quaife differential, more hp) I think it has truly come into it's own.
Personally, I am no Mopar fan. But, you have to give credit where credit is due. The SRT4 has single-handedly breathed life back into Daimler Chrysler's "American" small car line IMO. And, they didn't steal parts or a chassis from daddy-brand Mercedes to do it.
Maybe the SRT4's popularity will encourage them to make the Neon a much better car. And, that would be reason enough in itself for me to call the SRT4 car of they year.
Now, if we could just avoid all of those SRT4 vs. my uncle's JATO powered Sunbeam Tiger comparisons.