I love sharing the idea that tofu is good for you to eat.
Here's why: http://vegetarian.about.com/od/healthnutrition/p/tofunutrition.htm
If you'd like the general run-down without reading the article, I have listed the benefits
1/2 cup of tofu will give you the following nutrition:
10.1 g protein
5 grams of fat
227 mg calcium
1.8 mg iron
0 mg cholesterol
When comparing to 100 calories of beef, I think tofu wins. 100 calories of beef is ~1.2 oz and provides 8 grams of protein, 15 grams of fat, and 33.9 mg of cholesterol.