Shepherd is an occupational surname with a pleasant pastoral feel. It was chosen for their son by the Jerry Seinfelds, which might inspire others to follow their lead.
There are other spelling choices--Shepard, Sheperd, Sheppard--all of which lead to the friendly nickname Shep. Artist Shepard Fairey (original first name Frank) gained a lot of attention for his Obama HOPE poster.
Those various spellings are reflected in the surnames of such notables as astronaut Alan Shepard, "Winnie the Pooh" illustrator Ernest Shepard, actor/playwright Sam Shepard, "A Christmas Story" writer Jean Shepherd and actress Cybill Shepherd.