I've had the 6600 and the 7700 and love them both. I sold my 6600 once I got comfortable with the 7700. Some of the advantages are the larger harp space (and the extra 2" really make a difference), the free arm, the seam guide, the automatic tension and the FMQ. For FMQ the only thing I have to do is adjust the height of the quilting foot so that it just skims the quilt top. My dealer was not aware of this adjustment (hadn't read the manual?) but it makes a huge difference.
As far as a table goes, I've recently gotten the Aussie by Kangaroo Cabinets, which is part of Arrow Cabinets. I love it! It's got a large quilting extension which folds down as well as room on right where I've got a large Steady Betty for ironing and room on the left where I've got my cutting mat. I don't even have it open all the way. When closed it folds into a nice compact cabinet. Having the machine sit down in the cabinet makes a huge difference for FMQ, as does the quilting extension.
If you still haven't had a test drive, feel free to head down to Ohio and you can play with mine to your heart's content!
Lynda