One person's pick is sometimes another's pan, which is why you should collect at least three if not half a dozen names from friends and coworkers. (If you're short on names, try the American Academy of Pediatrics' referral site at aap.org/referral.) Call your insurance company about any doctor you're interested in but don't see on the list -- provider lists change frequently, and the pediatrician may have been added recently.
Next, scout out the location of the pediatrician's office. Given how often you'll be schlepping there, you'll want a short commute. The day that my then 8-month-old daughter suddenly developed a weird body rash, I loved that I was able to call, drive to the office, and be in an exam room within 20 minutes. Also look into which hospitals your candidates are affiliated with; you'll want one that's both convenient and reputable.