Quantum field theory's completeness I realize Quantum Field Theory doesn't include gravity at all. Other than that, does QFT completely describe all electromagnetic and nuclear interactions? In other words, does it describe (at least) everything the classical field theories did (other than gravity)?
Do the QFTs of the standard model describe all interactions of those fields? In other words, do QED, QCD, and QFD/EWT describe at least everything their classical counterparts do?
EDIT: The question has not changed; it has been reworded to use the phrase QFT more correctly.
 A: The answer to the question is yes. The framework of quantum field theory allows one to describe all interactions except for gravity. Different realizations of QFT take account for different fields of physics: For example, phenomena of electromagnetism are described accurately by quantum electrodynamics, while the strong interaction that describes how nuclei behave is covered by quantum chromodynamics. Together with the theory of weak interactions, these two theories form the Standard Model of Particle Physics. Apart from particle physics, there also exist quantum field theoretic approaches towards condensed matter physics.
The problem with a fundamental quantum field theory of gravity is that when one naively starts from general relativity and tries to quantize it, one runs into the difficulty of nonrenormalizability. This means that one encounters divergent integrals that cannot be removed by modifying the theory, making the theory useless. One solution to this problem may be approaching the issue from a different perspective and use the framework of string theory. 
The reason why quantum field theory is successful is the fact that at high energies and small distances, nature is dominated by both relativistic and quantum mechanical effects, and quantum field theory can be seen as a unification of special relativity and quantum mechanics.  
A: A quick clarification: quantum field theory is a classification of theories, that is there can be many different quantum field theories. The Standard Model is an example of a quantum field theory, and it does indeed describe all the phenomena we know about except for gravity. You might be interested to read this summary of the current (well, current as of 18 years ago) status of field theory by David Gross.
Although the Standard Model does not include gravity there is a different quantum field theory called N=8 Supergravity that does attempt to describe gravity. In the past I have seen arguments about whether or not the theory could work - it's too far beyond what I know for me to express an opinion.
