The Channing Knob, which is part of the Barrington Collection from Top Knobs, works well with both transitional and contemporary styles.  The square shape is great alternative to the simple round knob.  Available in 8 finishes (either in-stock or special order):  Black (shown here), Brushed Satin Nickel, Polished Chrome, Polished Nickel, Sable, Umbrio, Ash Gray, and Honey Bronze.