What Could Be Better? No-Bake Peanut Butter-Chocolate Squares

1 1/2 cups graham cracker crumbs (about 1 1/2 inner packages; in other words, about half of a box of graham crackers) 
2 sticks margarine, melted
2 1/2 cups confectioners' sugar
1 cup peanut butter, crunchy or smooth
1 cup chocolate chips
In a large bowl, combine the graham cracker crumbs, margarine, confectioners' sugar and peanut butter. Mix till well-combined. 

Spread mixture in a lightly greased 9 x 13-pan. Chill in refrigerator for approximately 10 minutes. While peanut butter layer is chilling, melt chocolate chips, in a microwave oven or in a double boiler on top of the stove. Spread chocolate over peanut butter. 

Cut bars into squares, but leave them in the pan. Return to refrigerator to chill for at least 1 hour.