What do you need to acomplish? Unless you have something specific in mind, its not going to be worth a upgrade.
If you are going to FF, it will pay to plan for it in advance, since all your lenses will suddenly seem to be 1.6 times shorter, and and EF-S lenses will not work with a FF body. Then, if you can't afford to buy lenses and FF body all at once, start acquiring a minimum set of lenses you will need for FF, and by then, a new FF body will be available.
If going to a 7D, all your lenses will work, but its not going to give any big boost to image quality, rather, it has advanced autofocus, video, and a much better build.
So what do you value most?
Video? Landscapes?, Wildlife?, Sports?, Weddings? Family and Vacations? There is a different best model depending on what you do, and no one model is best at everything. Life is always a compromise, we make the best one we can.