If you are on time and everything goes to plan then plenty of time.
I accept anything around 2 hours at any US hub, Atlanta is the only one we struggled, I think we had 1hr 55 mins and it was crazy busy plus luggage took ages to come thru. No problem any other time.
this is true of all the airports i've flown into except one - JFK...
if you're flying into kennedy, it very much depends on which airline you're on coming in and connecting to.....
2 hours can be enough, or no way in hell...
pretty much in all cases, you'll have to be ready for the JFK mini-marathon as everything is far away and many of the terminals are so dated, they don't even have moving sidewalks....
in other words, research is called for if you're entering the US at JFK..
on the bright side, if you miss your connecting flight and it's the last one from JFK to MCO, there's always the possibility that there's something at la guardia...that happened to us one year....
it was just DD and me on that trip...
they put us and another mom and her son on a huge bus all by ourselves and shipped us over to la guardia to catch the very last flight there to MCO...woo hoo!!! we made it...albeit by the skin of our teeth....as we approached the airport, the bus driver said, "i can't believe it...you guys are going to make it...i was sure you'd miss this plane too!!"
of course, our luggage didn't make it...but it got to our hotel the next day in the afternoon!!...not bad at all..
in any case, if you're flying into JFK, 3 hours is a must...
if you're flying into most others, you'll probably be ok with 2....