I used to have the Janome 6500 and now have the 7700 (DD has the 6500) and they are both great machines (as is the 6600). The 7700 and 6600 have the accufeed system so you don't need a walking foot. These are big machines with a lot of room under the harp. It depends on your budget. Janome also has some smaller machines that have a lot of features (12 pounds) and they have similar features. In addition to a bunch of stitches, I find I need need needle up/down a thread cutter and the ability to do a 7mm width stitch.
Kathyz gave good advice -- write down the features you want, find the machines that have those features and find the closest dealer and try the machines out.