My Bernina came with most of the feet that I needed. Are there some others I'd like, sure. I would like the couching foot, piping foot, circle attachment, felting foot and plate but I can't justify the cost for the few times I would use them. I did purchase the magnifying lenses because I needed them.
I think the 550? Comes with snap on feet so they are less money. Make sure that you know which kind of feet you are buying because the 8?? comes with different feet too.