I think it just depends on the child. We went to WDW when my now-5yo son was 13 mo; he nursed and fell asleep during the Legend of the Lion King show... slept through all that thunder! We took a 2 1/2 mo old last November and if there was room on the ride for him to nurse, he nursed.
Other places I have nursed my children: Pirates of the Caribbean, Great Movie Ride, Carousel, Carousel of Progress, Jungle Cruise, Backlot Tour (yes, even on those trams), Spaceship Earth, Listen to the Land, Hunchback of Notre Dame Show, It's a Small World, Peter Pan's Flight, Voyage of the Little Mermaid... those are all I can think of right now. I'm sure there are more!
Karen
1988: offsite
1994: CBR
1997: Poly
2000: SOG
Sept. 2001: AKL, Poly Lagoon Concierge, YC Lagoon Concierge!