Hi The Yank
I watch the new and used car markets in both the UK and USA as well as sometimes Belgium and Germany and the 'general' consensus amongst us petrolheads is the following
1. New Cars - Like for like models in the USA are substantially much cheaper in the USA. Even when the exchange rate is at its more 'usual' £1= $1.50/60 range, the list price in the USA for the same 'exact' car is usually around 30-45% less than here.
2. Used cars - Brand imaging has more of a direct impact on used car prices there than here. 'Volvo' in the US is seen as a 'premium brand' over here in the UK it's finally shook off it's 'dowdy old mans' car image it had for decades and in the last decade or so has become more of a premium brand. Used prices have therefore solidified for them here.
3. Engine choice - generally speaking like for like cars will get a similar lineup of engine sizes. Usually the US will get a bigger top model than to us here becuase we get ripped for the worlds 3 or 4th highest petrol prices. On the other end, becuase of that, the UK makes up for it with a Diesel variant or two and recently the hybrids although they're rare.
4. Europe has more 'manufacturers' of cars becuase there's more countries here! and they're closer to each other, the likes of Citroen, Renault, Skoda, Fiat, etc aren't in America becuase there's (relatively) no demand for small cars there. Look carefully though, many of the 40 or so marques you know of are owned by other bigger companies, and quite a few of them are US owned!

! - think (saab (GM) , volvo (ford) , vauxhall (GM), ford (well, ford!) , vw group i.e vw, skoda, audi, lamborghini, seat, Bentley (Daimler -Chrysler) etc, and in fact i think theres only 7 real distinct car manufacturer OWNERS and experts that will dwindle to around 3 or 4 in about 15-20 years or so.

Cheers! DtM! West London & Slough UK!