I have an older Bernina, not a Janome, but the utility of various feet is similar. More than half of my sewing is clothing, so I have bought many presser feet over the years, some I use often. I think I use my edge stitching foot more than the regular foot. It is also used for stitch-in-the-ditch, but I usually use it with the needle to the right or left of the blade to make professional edge stitching on hems, collars, etc.
The grooved pintuck feet are useful, too. I use the one with three grooves for invisible zippers and piping.
If you plan on free motion quilting, you might try different feet for that, since opinions vary over which type is best.