Walls out of square, how to align base cabinet?
Assuming you're installing cabinetry along the entire wall, I'd do this:


Find the point on the back wall that sticks out the most.
Measure out one cabinet depth and mark a line over the entire length of the floor. (Use a grout line as a reference-- even if your tiles are off-square, these are the lines your eyes will pick up as square.)
Install cabinets to this line, use shims to fill in the anchor points and the sides if necessary.
Tell the granite cutters that things aren't square, and let them deal with it.


I realize that this particular installation has a standalone on the end.  This really doesn't change anything -- You want the fronts of all your cabinets to be on the same line as you'll pick up the tiniest of inconsistencies, even with the fridge breaking the line.