Help Choosing and Installing a Natural Gas Boiler

We recently received this reader question and hope some of our readers can help.

Any direction you can send me to make heads or tails of quotes for new natural gas boiler installation? Munchkin or Buderus? 95% efficiency vs. less efficiency? Hot water tanks that feed off the heat of the boiler? Estimates within a grand of each other so (gulp) the price must be in the ball park.