We first tried a family dentist who (it turned out) had no pediatric practice at all, and then switched to a family dentist recommended by a friend - their practice sees lots of kids and we're very happy with them. Luckily, no cavities or xrays or anything much yet (my oldest is almost 7 and my 3.5 year-old will go for the first time next month.) I've also had to change my own dentist several times in the past 10 years - it's hard to find good dentists! I don't think you necessarily need a pediatric dentist, but you do want a practice that's familiar with all of the latest methods. Ask your neighbors for referrals.
I wouldn't worry too much about your son being afraid at this age - mine loves the dentist (they let him pick his toothpaste flavor and pick a treat out of a treasure chest - what could be better?!) They will probably learn to dislike the dentist after they have their first cavities, poor things. And it's not like you have a choice - Illinois now requires a dental visit by kindergarten, just like the health/vaccination records you have to provide. There's very little chance that he'll ever need dental work serious enough to be put to sleep, and if that did ever happen, you'd have time to get a second/third opinion.