Besides the Spit, I also like these:
A6M5 Zero-Sen. This is just such a proportional aircraft with such elegant lines. It is the only radial engined aircraft that I can say that about. I also understand that the A6M is a pilots aircraft, no vices at all. It has weaknesses as a warplane (to put it lightly), but from just a flying stand point and a beauty stand point, Horikoshi did a superlative job.
Fw190A Series. These fighters just look like fighters. Stocky, aggressive and to the point. Tank did a great job on this aircraft, it looks like it should. Where the Spitfire is the elegant duelist that wins by agility and grace, the Butcher Bird is the brawler who wins by meaness. I agree with Urchin, the Dora horribly distorts, like a caricature, the nature of the Fw190.
Mosquito FB.VI. This aircraft is sleek and clean. Nicely rounded tail and stepped wings create and thoughbred look that makes it look like one would imagine a successful multi-role aircraft would look given the technology of the day. This was the aircraft used for pinpoint strikes in cities and on parts of buildings in WWII.