see I'm going to plan ahead, when my future wife has our 2nd kid via C-section I'm just going to have the doctors hook some twistie ties up to those bad boys...
life is long man and you never know what the future might bring. I would reccomend against it. however if you get it done, get it done via the method where the vas are clamped rather than completely severed increasing the possible of a reversal in the future if your life situation changes.
the other option would be to wait a year or so until the male birth control pill is perfected and go that route.