i don't know what kind of place you're looking for, but my 2 favourite restaurants to go eat out for a special occasion are Lele (Costa Rica & Thames) and El Ultimo Beso (on Nicaragua betw Thames and Serrano). I think the food is better in Lele. They are both beautifully decorated, but in different ways. Lele has different coloured rooms, and el Ult Beso is all white, but not modern, rather romantic. Another restuarant I love for its great menu is Dale Perejil Al Toro en Estado de Israel (between Yatay and Jufre). They have lots of traditional Argentinean dishes that you rarely see on offer in most restaurants, plus non Argy stuff too (great for me, since I'm a vegetarian...). The place itself is also lovely, an old casa tipo chorizo with a patio to eat outside if you want