Its not that bad, many worse things you can eat. The reason why people say white rice is bad is that it can be considered a "processed," or "refined" food.
The processing is that the natural bran component of the rice grain has been removed. This eliminates the natural fiber, various Vitamin Bs, and other nutrients that are good for you. The white rice folks will then spray vitamins and minerals back on the rice to try to put back the nutrition they removed in the first place.
They still miss some things, and the most glaring omission is the fiber.
Why take off the bran and attempt to make up for it with artificial vitamin addatives? Because the fiber contained in the bran coating on natural brown rice makes the texture slightly more chewey, and it also makes it take twice as long to cook, both considered negatives by the vast majority of rice consumers.
When you eat white rice, since the fiber for the most part removed, your system digests the grain very rapidly, breaking the rice starches down into glucose (sugar) much more rapidly than if you ate brown rice (the bran coating of fibers slows digestion down significantly).
Essentially, what you get with white rice is an influx of sugar in your bloodstream that is not mitigated by the natural slowing action of the bran fiber. This is why some consider white rice not terribly healthy.
This thread makes me all sorts of happy, and Grady is completely correct with his explanation. With that said, I'm glad some folks have already mentioned the whole skinny Asian phenomenon (it's not really a phenomenon). We can all talk about daily caloric intake and white rice being a simple carb, which invariably breaks down to turn into sugar... which then turns into fat. And while there isn't really any refuting that being fat is a social stigma in most Asian countries and that most Asians tend to eat far less than most Americans, there are definitely those Asians that have eaten their fair share of white rice their entire lives and haven't gotten fat because of it (me included).
A lot of it has to do with one's natural metabolism. Also, please keep in mind that in many Asian countries like Korea, Japan, and China... fish is a staple in everyone's diet. NO ONE just eats plain white rice or brown rice. If some do, I've never heard of such a thing. Wandy loves him some chicken and rice, and he's by no means a fatty. Many Asians love to eat fish and rice, and a vast majority of that fish has Omega-3's and other good fats that help break down the bad fats in a person's body. In other words, I don't think the skinny Asian-white rice theory can really stand alone without introducing additional foods that we eat along with our lifestyles. Asian martial artists and Asian videogamers also tend to have significant differences in the way they eat and burn calories.
With that said, brown rice IS healthier than white rice. Plain and simple. If you can get by the differences in texture AND you're trying to lean down, it'd be a far more intelligent choice for you. I like to mix natural brown rice, brown sweet rice, and barley in a secret ratio taught to me by my Korean mother (in the rice cooker of course). And it comes out more delicious than most white rice dishes.