Ok, I bought a new car a couple days ago with a very upgraded radio/sound option. It's got the worst reception (especially static) and the worst selectivity (stations bleeding into each other and stations not tuning in well) of any of the dozen or so cars I've owned in my life.

Before I go to the dealer and complain, I need some advice from people who know about these things. Is it likely (or even possible) that I've just got a bum radio (perhaps poorly made at the factory) or would you be betting that it's the radio design that is generically poor?

I "would be betting" that your antenna is a land embedded between the defogger sections of the rear window and that you have metallic tint on that window. It is noticeably directional on FM, favoring front and back with greatly reduced gain to both sides. Go to a stereo shop and have them install a real car radio antenna and your problems will go away.

A little more info please? Make and model and year of the beast that you bought would help?
N9ZAS

Since you quoted me and not isFred, I will assume the question was addressed to me.
I will suggest these three manufacturers who each have a gain mobile FM antenna:
Fanfare also sold by C. Crane
Magnum Dynalab and Metz
Fanfare makes a special model tuned to the Japanese FM band and the reserved portion of our FM broadcast band for noin-com fans.

A little more info please? Make and model and year of the beast that you bought would help?
N9ZAS