If you are planning to spend a full day at Disney's Animal Kingdom, you should be able to ride everything regardless of the wait times. If you are not, plan accordingly.
No other ride at AK will draw more wait times than Avatar: Flight of Passage. At it's peak, FoP carried wait times of over 3 hours, now, year's later, the ride still holds nearly 90 minutes or more and typically...more.
If we see 90 minutes, we wait in line but most of our trips have been met with times of nearly 2 hours and after having ridden it previously, that's a bit much for another trip to Pandora. Still, if you haven't ridden it, consider waiting the 2 hours. The line waves through really lush vegetation and is at least enjoyable once inside.
Worried about the time? Next to FoP is Na'Vi River Journey and that ride will typically carry 45 minutes to an hour and sometimes a little more but not much.
Take the time you were going to spend waiting for Na'Vi River Journey and subtract it from the time at Flight of Passage as that is by far the superior ride and possibly the 2nd best ride at any Disney World park.
Moving from Pandora to Asia you will find Everest, the parks only rollercoaster. As a coaster, it's o.k. There are far better for coaster afficianados but the wait times typically are less than an hour and a single rider lane can shorten the ride to less than 10 minutes even on the busiest of days.
Dinosaur is another ride that if the time is good, you could take the time to ride but if you miss it, you won't care. Still, if you are choosing between Dinosaur and Kali River Rapids, choose Dinosaur. River Rapids will greet with you wait times of over an hour and on really hot days, that increases to nearly two. The ride takes about 5 minutes and no, you really don't get all that wet unless you end up under the single waterfall that typically hits one person. The draw of Rapids is the relief from the heat but it doesn't relieve anything.
The other "must-do" ride at AK is Kilimanjar Safari and while the wait time may exceed an hour, it is far more worth the wait than Dinosaur and River Rapids combined. Boarding a large Jeep style vehicle you ride through an open safari where animals can stop you literally in your tracks as they cross in front of you or decide to just lay down and block you.
Finally, we head to the Disney World park that everyone goes to, Magic Kingdom.