arguments for him still dreaming: while mal is out of his head finally, along with the wedding ring, there is no interpersonal dialog between the characters after they wake up on the plane. also the house that he goes to to reunite with his kids and michael kane is a house from his dream universe. although the kid actors are different in the credits it's obvious they are in the same clothes as in his memories. while he might have expunged mal from his head, it is fully possible all the characters are projections. in the van going into the water, cobb is not revived with oxygen, neither is saito. there is also a possiblity that cobb is still dreaming in yusuf's basement after yusuf stops cobb from spinning the spindle (thus preventing him from seeing if it falls over or not).
arguments for him not dreaming: for the first time in the movie he does not care if the spindle falls over or keeps spinning. every other time, he watched it.