Possible Duplicate:
In Gmail, how do I set the default email address for a contact that has two email addresses?
In Gmail, with a contact that has multiple email addresses, how do I set the default email address?
The order in which they are defined does not seem to have affect. Also the "tag" home/work/other does not seem to have affect.
Is it, perhaps, some sort of "most used at the top" kind of thing?