Nah, I stick to my XD for self defense and leave the martial arts to the hobbys.
I agree with Don on this one. If this is just a "what if" sort of scenario, then the debate can be endless. Innumerable threads have been posted on this very same subject. The short of it is, nothing trumps a gun in regards to self-defense, provided you know how to use it and are aware of the legal & ethical ramifications of use-of-force.
There's a world of difference between "self-defense" and "combat"...and I'm presuming you mean self-defense. First, I think you need to properly assess what sort of situation/scenario you typically find yourself in when the concern about "self-defense" arises and then examine your motives and what the proper course of action should be (i.e. legal & ethical concerns).
If you are overly concerned about self-defense and fear for your life, then it would behoove you to legally acquire a concealable handgun (with the proper training & permits, of course). Even in feudal Japan, hand-to-hand was the "last resort" for the samurai when he found himself engaged in combat.
The real issue is having a self-defense mindset, being alert and aware of your surroundings at all times...keeping your guard up. Simply being observant of all that is going on around you and not intentionally placing yourself in dangerous/threatening situations (e.g. going to the "wrong side of town" and the like) are the single most effective means of self-defense.
The other issue is if you have a killer instinct or not. This not in the sense of actually killing, but rather in regards to if you are willing to fight. It doesn't matter what style/type martial art you study...what matters is if you have the ability to "flip the switch" and fight for your life when need be. Some folks just don't have it in them.
For what it's worth...