Thanks a lot gRomoZeka, It-ogo and Throbert McGee!

Quote Originally Posted by Throbert McGee View Post
The only thing I would add is that in the example you gave ("What kind of fruit do you like?"), I'm pretty sure that most Russians nowadays would prefer to use какой instead of который -- thus, Какой фрукт ты любишь? Or as an example of the feminine accusative, Какую водку ты любишь? And in a seafood restaurant you could ask, Какая рыба у вас свежая сегодня? ("What kind of fish do you have fresh today?" -- note that какая, рыба, and свежая are all in the nominative, just as when one says У меня друг or У нас собака, etc.)

It's not that using который as an interrogative is grammatically wrong, but simply that it may sound a bit old-fashioned and uncolloquial in a question of this type, so in general it's better to use какой.
It´s really useful for me to know about it)