I'm a fan of all of the taqueria's in Madison. Prices were reasonable and we tried five different tacos, which were pretty tasty (fish, beef tongue, steak, pork, and a combo). I was also pretty jealous of my friends who got the fajitas, so would have to try that next time. They have a machine that is churning horchata that I'd love to try in the future also.
I would say that if I had to choose though, Tienda Los Gemelos still ranks number one, but that may be a personal bias and you can't go wrong here.