Los Mariachi is the place to get excellent Mexican food in Racine. They have 2 locations, but both are very much the same as far as the food and setting go, so these comments are specific to the Douglas Ave restaurant, but apply to both.
The location is a little scary, if you've never been in. The front of the building makes it look like it's closed, and you have to park in the back. The big metal doors are uninviting. You DO want to get over the first impression, though, because the food is too good to pass up. The dining area is Mexican themed, energetic, and somewhat loud.
My personal recommendations are the Enchiladas, Burrito, and Chimichanga. The sauces are better than any other place in town and the vegetables they use always seem to have the perfect taste. The vegetables are always fresh, even when they are out of season.
They also offer carry-out, so pick up a carry-out menu if you ever stop in.