I make square or rectangle for baby quilts. Just whatever I want to make at the time. My next size up is twin. I make approximately 60x90 for twin and sofa quilts. Then my DD has a full bed and she likes 90 square. DS has a queen bed and likes 100x100. Then I have a king and make 115x115. I think a wide rectangle would probably fit better, but the square is easy, any side can be the top, and it is easier to layout a square IMHO, and it definitely covers our feet, even my 6'2" DH.