Steaks: La Parilla (the restaurant, not the taco/sandwich branches) on Prolongación de Montejo - about 1 block north of San Francisco de Assis/Office Depot - on the west side. They pre-cut their steaks to local style thickness (1/2"), but the meat is tasty and you can eat a nice combination of arracheras, rib-eye, etc as a part of the almuerzo buffet - cooked over carbón vegetal - and yes, they do prepare a good rare steak (upon your request). Local color - nice folks - good local food.
The very best steaks and cordero in Merida are found at La Recova - about 5 blocks further north on the east side - but this is an Argentine style place, more expensive, and more popular with the trendy crowd.