Yes, this topic's been around for a while, but let me try my hand at it ... from just outside McKeesport, PA (Pittsburgh market) ...
530 RVCI ... I've never received anyone at 530 in this area. WWCS-540 out of Canonsburg probably affects it, but can't say that for sure anymore.
640 KFI ... Not this far east. During the day it's WHLO out of Canton-Akron. Not sure what's there at night.
730 XEX ... WPIT-730 out of Pittsburgh day and night.
750 WSB ... Not a bad nighttime signal.
760 WJR ... Used to be better during the day, pre-WKFB-770. But still can be found on occasion.
850 KOA ... Not this far east. Local Catholic outlet WAOB-860 dominates and we're right between Cleveland and Johnstown. (Though the station on 850 in Johnstown reportedly is off the air.)
870 WWL ... Comes in at times at night.
880 WCBS ... At times it almost sounds local at night. Used to get a Columbus, Ohio, station on 880 during the day.
890 WLS ... Likewise, almost local sounding at night.
1000 KOMO ... Never. Chicago's AM 1000 almost is scannable at night.
1110 KFAB ... Never. WKZV Washington, PA, by day, when it's on the air, WBT at night.