This blog post lists the maximum wait time for passport control at 10 major United States airports.
The worst is JFK (55 minutes), the best is Dulles (34 minutes).
As the blog post notes, it’s certainly worthwhile to apply for Global Entry in order to bypass almost all that delay. Other speedup methods are Automated Passport Control kiosks and a new smartphone app named Mobile Passport Control.
A big plus for Global Entry is that it includes PreCheck, so you can bypass the longest lines at security checkpoints in the United States.