I have more than 100 contacts in gtalk, while only contact with 2 or 3 of them everyday (contact plasmoid doesn't fit the panel) , but currently I need to browse or search against a long list for some one I need to talk with. Since I've been use N9 for long time, I prefer N9's way, people don't use contact list usually but directly use the UI of log viewer, that they can see who did they contact recently (and maybe 1 or 2 lines of last conversation), and those contact would be put right at the head of the list. When people really need to find some else, they can use a complete list. Reproducible: Always
I agree that such "automatic" solution would be awesome. In the meantime you can create a special group and just drag your favorite contacts in there as a sort-of workaround.
*** This bug has been marked as a duplicate of bug 324378 ***