The feet I use the most are my 1/4" piecing foot, free motion quilting foot, and walking foot. I do also use my open toe machine applique foot a lot. And another foot I do love is the edgestitch foot. Other than that it will depend on what kind of sewing you do and what feet you might want to play with. There are so many to choose from, each doing a specific task. Some are quite costly though, and I would only buy them if you knew you were going to be using them a lot.