How do you decide?

Our house is a custom build and not a builder's design.  That being said, the perks of  a custom home are exactly that, the house is completely custom.  We choose everything!  We get to pick out whatever flooring we please, whichever windows we want, any doors, any roofing tiles, the world is ours. 
Yet, our plumber recently provided us an offer that inclued fixtures.  I know we should purchase our fixtures, well most of them through the plumber.  Although his prices may be a little higher than what we could get from an internet company, we get peace of mind that our fixtures will arrive in good shape, come with a warranty, and that the plumber's price will not increase for installation. We already have sinks for the master bath, children's bath and cellar, but otherwise, toilets, showers, the guest bath sink, all will come from the plumber.  The plumber offered us his version of "builder basic," Keramag's series, Renova Nr. 1. 
I know its a little ridiculous, but I had different views and ideas for my toilets.  Mr. B always brings up the fact that a toilet is a toilet, and well, you know how we use toilets, they're not furniture pieces.  On the one hand I see the practicality of this argument.  Maybe its because my dad is a plumber, or maybe its because I am attempting to recreate a New England colonial in my little house, but I'm not so happy with the practical approach.  
I really like Villeroy and Boch's Hommage collection, and Kohler's Portrait collection. 
The problem is that we're starting to reach the edge of our budget, something which makes me a little uncomfortable.  I think these are the decisions that are also difficult.  Should we go with the more expensive Villeroy and Boch fixtures, or stick with the more basic fixtures, accepting that we will change them out in the future.  Will we get around to changing them out, as dogs and children expand our lives, and our focus shifts away from our house as time passes? 
We are going to ask Mr. Haag for the prices of both the basic fixtures and the Villeroy and Boch Hommage fixtures.  But in the end, how do you decide?