What brand of coffee is the best?

OK, so I tried some cups of coffee these last few days.  Basically the main "change" on each style is the amount of milk for each.  Expresso's is finely ground against the little bigger coffee for the regular coffee makers.  My problem is that I am too "new" at this to actually identify the acidity amount on each.  I'll have to find out the best blend to use it as the "house blend"...  but when I go to the supermarket and face all those brands, I feel lost!
Somebody told me that Arabica coffee is better because it is not too acid, and works well with everything.  I am a firm believer that we need to offer something of high quality, something that people would enjoy very much, and would match to have with some good dessert.
Again, many details of so many thing dancing in my head...  The lease dealing is going well, but we are not done yet.