Race To Train, Or Train To Race?

I’d like to throw this out for discussion. What is better: race often, because racing is the best training, or race rarely, and specifically train for each race to get a result? Is there a happy medium between these two points? I realize that your answer will depend to a great extent on whether your personal life situation allows you to race frequently, but assuming that it does, which side of the spectrum do you advocate and why?

On a similar note: when is it appropriate to "train through" a race? Or is this really an [pre]-excuse for poor performance?

As BikeSnobNYC puts it:

Despite the fact we're still in the middle of the Tour, the fact is that road racing season's basically over anyway. The astute rider has already written it off and begun focusing his or her attention on cyclocross. The key to a successful racing season is to always live a minimum of four months in the future, mentally-speaking. That way you can dismiss your poor performances as simple preparation. Sure, you may not get anywhere near the front of the pack in a road race this summer, but you're just trying to get some intense mileage in so you'll be ready for cyclocross season. Poor mountain bike racing is even easier to rationalize--you're just doing that to improve your bike-handling. And of course once 'cross season does begin, you're still under no pressure to get results because, really, you're just doing it to maintain your form during the off-season. With the right attitude, you can surf an entire year of racing like a great big wave of mediocrity. Winning is for dopers and sandbaggers.

Without discounting the few remaining road races this season, I’m already thinking about my approach for next season. Please share your thoughts in the comments.