What makes a good martial art?

So, what do you think makes a good martial art? And how do you judge?

A lot of people try to compare which martial art is better by comparing the very best practitioners each art has produced. This ends up being an argument over whether Bruce Lee could beat Ueshiba Morihei or something equally silly and pointless.  When your comparison involves people of great talent, what you end up comparing is the relative talents, not the martial arts.  I think it may be impossible to compare martial arts in a general sense.

Each martial art is created and practised with a different set of assumptions about timing, spacing, what weapons are being carried and what kind of attacks will be launched.  You can compare the effectiveness of a martial art in a particular scenario, but there are so many potential scenarios that all you are left with is that a particular art is better suited to any one scenario than another.  It still doesn't give you a clear base for comparison, unless you're convinced that potential scenarios come in a very limited set.  Is your scenario based on a confrontation in a bar, a bouncer at a nightclub, a police encounter on the street, a prison guard dealing with inmates, a soldier on the battlefield?  Different skills will be demanded for each of these.  And unless you work in a field where confrontation is part of the job description, the odds are good you won't need combat skills in your day-to-day living.

For me, it comes down to what the art offers me. Does it enhance some set of combat skills? Does the art address more than just the technique aspect of combat? Do the skills taught have some chance of being relevant for something in your life (not a fantasy of conflict, but what you're really liable to encounter)?
Are the skills learned applicable to anything besides actual combat?

So tell me, what makes a good martial art for you?