Sticker price is the main factor.
As many have already stated, all are important, but I went with sticker price because that's usually the one factor already decided before research begins, and budget is almost always the second decision made (the decision to buy at all being the first).
Also, each factor listed has the potential to affect any other. For instance, you may be willing to go slightly above your budgeted price if the product is outstanding in any other category. A free professional in-home calibration is worth an extra few bills, isn't it?
That said, no one factor can have more of an effect on the decision than sticker price. There will always be those with unlimited funds but for those of us in the real world, it's all about the $$$.