I would agree w/ others that Hy-Vong is a little gem. On 7th (where 8th street is one way) the new Graziano's is worth a visit. I live 2 blocks from the Gables Graziano's and visit regularly. Very diverse menu, food always fresh, well made and service is exceptional.
Starting from downtown moving out...
La Moon for late night and anytime Colombian street food, go for the supermoon perro.
Las Tapas de Rosa, while not great, is not bad either. That being said, I had an enjoyable dinner here in this tiny storefront right next to I95 and 8th. Huevos estrellados, fabada, garbanzos, jamon y queso, sangria, etc.
I only stopped by Mr. Yum once but it was enough to know I need to go back. Small japanese/sushi place, was slammed the night I dropped by for takeout. Sushi looked great and I enjoyed everything I ordered.
Some of the best authentic tacos around are at Mi Rinconsito, try the adobada (pork). Really really good and pretty damn cheap.
Versailles for experience cuban. Its fine not great food but funny scene and its a landmark. I stop by for takeout mariquitas and a sandwich.
Hy Vong is more or less across the street from Versailles, and while I haven't had the chance to stop by yet, its on the list and seems to be regarded as the only place for good Vietnamese locally.
Hy-Vong Vietnamese Cuisine
3458 SW 8th St, Miami, FL 33135
3555 SW 8th St, Miami, FL 33135
Mi Rincosito Mexicano
1961 SW 8th St, Miami, FL 33135
1945 SW 8th St, Miami, FL
Las Tapas De Rosa
449 SW 8th St, Miami, FL 33130
La Moon Restaurant
144 SW 8th St, Miami, FL 33130
I am a fan of Hy-Vong, although some say it is not authentic Vietnamese, and I agree it is quite different from my closest to authentic experiences in the pacific northwest, it is still delicious food. It is an all night thing, get there either at 6 pm or 8 pm. It gets full right when they open and it takes 2 hours to eat so tables clear out every couple of hours. Mi Rinconcito for Mexican is good, and I also happen to enjoy Taquerias el Mexicano. I like the experience at Versailles, although it is not the best Cuban food around, it is fun to go especially with family. Not exactly on calle ocho but close is Salmon Salmon (2907 NW 7th St), GREAT Peruvian food. I have heard good things about Mr Yum and Las Tapas de Rosa, but haven't been yet.
I only visited Mr. Yum once but I was thoroughly underwhelmed. Had sashimi and a sushi roll. The fish selections were completely pedestrian, the fish was kept too cold, the rice in the roll was cold and gummy. Flavors were completely muted and textures were all wrong. Maybe the Thai food is better.