Well, no, India and China have the longest lines for EB-2 only (India at 10 years, China at 5) -- of the categories with any waitlist, this is the second shortest (After F-2A) for the longest two waitlists. Other employment based categories, the longest lines are the Phillipines and India.
For family-based, in every category, the longest waitlists are Mexico and the Phillipines (though the order between those two varies between different categories), and every country has a waitlist because total request exceed the total quota (on the employment based side, this is also true of the two components of EB-3, but none of the other categories). The single longest waitlist of any category (family or employment-based) is F-4 from the Phillipines, which is currently nearly 24 years.
Depends on which visa category, for some its China and India, for others its the Phillipines and Mexico that have really long wait times. I think there are a few others that have short but non-zero wait times for some categories, but that changes more frequently.