The next version of Ubuntu is currently, as you may already know, undergoing some fairly drastic interface changes. Ubuntu will be abandoning the use of the traditional GNOME panels and instead use an improved version of their Unity interface.
Lurking through several bugs on launchpad, I stumbled across an interesting one with one interesting mockup in particular.
While its just a suggestion mockup, I think it actually looks rather slick. I’m not saying its the best approach, but certainly one worth noting! According to a follow-up comment, this design is similar to what Gnome Shell is doing, but I’ve not yet looked into Gnome Shell so I can’t confirm this. Either way, its a smooth approach.
Currently Unity doesn’t have a method of letting you know which application’s menu its showing in the top panel. There is an indicator icon in the side dock/panel, but as best I can tell they are planning to add the app name to the top panel similar to the way Mac OS X handles this. Maybe it will be in some Unity updates tomorrow!