I like 'go girl' and don't have a problem with 'guys' for a group of mixed gender (although probably only if the group is about the same age or younger than the speaker). I also associate 'lady' with upper class and an uptight attitidue to manners and doing the 'proper' thing - so I prefer woman.

I must admit I found it a bit strange when my bosses secretary called me 'doll' in a work email last week.