I notice a lot of Americans in Europe wearing chino khaki trousers. They look like they are trying ot make an effort to be smart looking (bless) but it just looks underdressed or strange.

I think in the US- the "uniform" of chinos, white button down shirt (eg Ralph Lauren Polo Oxford style shirt), stripey tie (often red silk) and navy blue blazer can look appropriate. In Europe it just doesn't look right.

IMHO anyway- I find chinos less formal looking than a finer wool trouser. A perfect Friday trouser- but not a business trouser.

Jeans- depends on your age and style.