I agree with T. Pacifico is better than Corona (though they're from the same company--Cerveceria Modelo SA de CV). This company also makes Modelo, and Negra Modelo. While in Mexico, I also took the liberty to try Negra Modelo. It was a good standard dark lager.
This is their line up:
The other big Mexican company is Cerveceria Cuauthemoc SA de CV. They sell Tecate, Dos Equis, Indio, Sol, Carta Blanca, etc.
Interestingly enough, both of these companies have [seemingly] big buildings in my city. I know Cuauthemocv has a factory near my aunt's house, because we drive by it all the time (when I'm there). And I do recall Modelo to have some type of distribution center in downtown Culiacan; lots of trucks and stuff.
Beer is easily available, and I've seen Caguamas and Ballenas sell cheaper than a 2liter bottle of Mex Coke. You can buy it almost anywhere. In Mexico, they have these stores called "Oxxos" which are similar to 7-11. They all have beer available. And then there are the stores that either sell Cuathemoc or Modelo products. It seems that the big companies franchise out these little stores. At these, you can buy in bulk for a party. Tecate Light seems to be the party swill of choice there. You can get an 8 pack for less than $5, IIRC.
Where I come from, right now (at the time of this post) given that it's summer in July, it's probably like 96 degrees with 29% humidity.
Right now, it's actually 93 F with 52% humidity and clear skies. http://www.google.com/search?q=culiacan+weather+forecast&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
The point is, it's fricking hot--like Phoenix but it feels like you are in a swamp, even though there aren't any.
Beer has this refreshing property. So in my opinion, Cold Ones are as essential as Air conditioning in Sinaloa.