Guys - 'preppy' doesn't necessarily mean "well dressed". I know guys who end up looking like dressed-up librarians when they go preppy.
Alright - I think we should reframe that idea and call it "being dressed to impress". You can be wearing rocker-garb, and still look like you put a lot of effort into looking good, if it is well put-together. 90% of men do not know how to "put an outfit together" - they automatically think that throwing on a suit or collared shirt with designer jeans makes them "preppy" or "dressed up". I think that Soma is a superb dresser - you guys should ask his opinion about what a 'good dresser' is.
Anyway, about Euros and Asians - unless you've been to both places and are intimate with their popular culture (meaning how they behave in theri nightspots, what 'look' is popular, etc.) - you'll notice that they wear form-fitting clothes and neatly tailored pants/blazers/jackets/shirts/t-shirts that give them a decidedly more "dressy" look, even though they are just wearing jeans. American clothing brands on the other hand, have unflattering baggy/boxy cuts and uninteresting designs/colors that just make everything look 'dressed down'. What does this mean? It means that clothing companies/designers in both nations are just giving the consumers what they want - the Euro/Asians what is dressy, and the Americans what might be considered 'sloppy'. For example, all the brand names that us Americans might only wear on special occasision (and might otherwise consider "overkill" in other situations), are standard everyday garb in Europe, and Japan/Korea, for example. And because of these cultural aesthetic differences, women from Europe/Asia have 'higher standards' in mens' fashion sense, compared to America. I see college guys go to class in sandals, basketball shorts, and sweatshirts all the time, and not to sound like a fag, but it looks kinda 'gross' and grubby. If you did that Italy, Germany, Switzerland, Japan - you would probably be mocked behind your back.