When hiring I like to see all resumes. For many Technical positions the best candidate is not the one with the right buzzwords but the one with passion for the job and technical nous. HR often weeds out the resumes I am interested so I like to see them all and spend the effort.
I agree many hiring managers will not go past the 2 pages, but I think you are hiring to find the best person for the job long term, not to find the person easiest to hire. I do focus my resume for the job, but only keep it succinct with the thought of getting through unknowns with no understanding who cull the resumes.