another way to get around that dreaded thermal bridging is to build a 2x4 wall on a pair of 2x8 plates. stagger the studs, so that the only locations where a stud passes from inside to out is @ doorways and windows. it certainly uses more resources as you may have to go essentially 12" oc (when taking into account the stagger) to be able to hang sheathing @ 2' oc... fill with cellulose. we're planning on this system (if we can get enough shear) or a 2x8 traditional wall with DOW SIS as the sheathing (still researching the materials for this option.

and - for those who worry about thermal bridging - what type of windows are you using - seems you can have the greatest wall system in the world - but if you punch it full of holes, esp holes that are not effective at blocking solar gain and retaining heat or cold from the inside... your wall is pretty useless. the wall is often greater than the sum of its parts - but that works inversely as well.