Some friends of mine, native speakers of American English, insist that conversational usage of 'whom' in as good as non-existent; unless in some frozen expressions, a native speaker will always use a 'who'. Other say that, as other ungrammatical usages, this indicates poor education. Some others claim that while substituting who for whom in some constructions, like in the beginning of a question, is not uncultured, in others a properly educated person would use 'whom'. I have also heard opinions that this depends on the age and origin of the speaker rather than on his or her cultural level.
So my question is to native speakers, not necessarily American: how do you personally feel about that and do you use 'whom' yourself?