I previously submitted this idea at the Ubuntu Brainstorm site, but they don't seem to do a thing about it. As far as I am concerned, it is a really good Idea, for my solution got around 491 votes in favor. Here is the link, anyway http://brainstorm.ubuntu.com/idea/18562/

You don't have to navigate there to see it, I will write it down below.

The gnome-panel is sometimes painful to organize. And I say painful because when you want to move an item, or remove one, you have to unlock, move and maybe lock again, every item. 

My solution: give every item, on it's properties, an option to gravitate to one of either extremes of the panel. This way, when you remove an item the items will fall back to either side they gravitate to, making your panels look clean without an effort.