I visit Michigan quite often. We are all canadian citizens. Lately after sept11, we are being asked where we were born. Nothing else.
As for landed immigrants, I know for sure that if you are born in one of Islamic countries, you will be called in for questioning. I've heard that a person whether he is a citizen or landed, if he posesses a muslim name, the US border security would like to probe in.

Best option is to carry the passport+landed paper, rest of the IDs, proof of employment and clearly state the reason for visit (visiting a relative in Buffalo, NY) and the intended stay. Let one person answer all the queries.