| I virtually never hear the term "Christian name" here in the USA. I bet must Americans wouldn't be sure what it means. I'd be interested in what my Jewish and Islamic friends think of the term. I also virtually never hear the terms "surname" or "family name".
I think the confusion results from the fact that we (i.e. Americans and Europeans) seem to divide the name into different significant segments.
E.g. if your full name (what do you use for that concept?) is John Allen Smith then your "first name" is "John", your "middle name" is "Allen" and your "last name" is "Smith". I don't know of any term that describes just the grouping of "John Allen".
If your name were John Allen Grady Smith then you would have two middle names.
As for names with word breaks in them, like "van Rossum", the whole string is collectively called the "last name", though I'm sure Guido and others have many stories about the confusion of such a name.
-Miko | 
