Iron Man 3 is officially a successful movie. Making $500 million overseas before releasing here and making $170 in one weekend. After the worry of will people actually go see this wore off and another successful Iron Man movie had been made it was time for a small celebration for some of the key members who made this all happen, and to talk about the future.
A dinner was held, organized by Robert Downey Jr.'s wife, with Kevin Feige (Marvel Studios president), Alan Horn (Disney Studios president), Shane Black (Iron Man 3 director), and of course Robert Downey Jr. himself. The dinner was to both celebrate the success of Iron Man but also to discuss where it is going, and more importantly if Downey will be a part in that future. Currently, if everything stayed the same, Downey's final role as Tony Stark would have been in Iron Man 3.
Some say Downey is already into talks about reprising the role for the next two Avengers films but currently an Iron Man 4 movie hasn't been put on the table. Makes sense for Downey since he has openly said the Iron Man suit isn't comfortable to wear and at age 48 he may be getting too old to kick butt on a biyearly basis.
However for Marvel and Disney there is no hero like Tony Stark in their stable, specifically the Robert Downey Jr. Stark. Compared to the other pillars in the Avengers franchise Iron Man rakes in the cash like no other and unlike those actors is probably the least replaceable. Iron Man has the advantage of having been released before both Thor and Captain America and unlike the Hulk movies has been able to keep consistent.
So how knows at this point, Downey seems likely to be an Avenger for the foreseeable future but Iron Man 3 may just be the final standalone Iron Man film.