I have a contact with iMessage, AIM and Google Talk accounts. When using Messages to open a new chat with her, I'd like it to always default to Google Talk if she's online -- instead, it seems to pick a contact method at random. How can I make it use Google Talk by preference (without deleting the other accounts, since I want them to be available as well)?
As of 10.8.2 the only way to do that is to keep that particular conversation open all the time.
Another workaround is to copy the preferred google talk info to another contact name with just that. "Jane googletalk" so you know which is which.
On a conceptual level i don't think they will fix it. It's the same with multiple phone numbers... you have to select which one each time you call... you can't have a preferred number, UNLESS you Favorite that number.
Alas there there is no favorite option in messages for mac.