How does define American cuisine? In other countries, American cuisine is pizza, hamburgers, apple pie and ice cream. All this is embodied by the plethora of fast food restaurants outside the US. All this is STANDARD American food, but times, they are a changin'! The U.S. is not a nation of only European-based cultures, and so American cuisine is a international manipulation of cooking styles and food combinations. It is constantly changing and branching off into new styles: California Cuisine, Microbreweries, and Eclectic to name a few.
There are two types of locales in which to eat Mexican food. There is the hangout where you don't really sit down and you get your hand-held burrito brick. Along with this kind of place is the sitdown, but dirt-cheap restaurant, where you get the Mexican mainstays, with rice and refried beans. Cheap, but good! Nowadays, imitations of these types are springing up everywhere. They have modified the dishes to a more modern style--ie. kale & turnip meatless tostados, lowfat refried beans, cajun chicken burritos, etc.--or just don't remain true to the quality of the smaller places--wilted lettuce, overripe tomatoes--they're just in business to capitalize on the Mexican food craze. As for these larger restaurants or chains, such as El Torito, Chevy's or Carlos Murphy's, these can generally be trusted, but be wary of any place that offers a free pineapple margarita with every order!
If you're looking for a beef-laden meal, a steakhouse is a good bet. You can almost always find coupons in the paper for some $XX.99 deal, which includes salad, several types of meat, drink, and dessert. Otherwise, these places have special everyday deals for 1-2 lb. steaks. Be wary, though, of places like Morton's of Chicago--they'll charge you per item (and the prices are steep - $6 for a baked potato)! Generally, though, a steakhouse is a good hearty meal deal!
I hesitate to name a category "Vegetarian," because they tend to be salad bar places, and there are not high numbers of them. The advantage of a salad bar or vegetarian restaurant is that they don't charge exorbitant prices, because they don't serve expensive meat; and many are all-you-can-eat!