Double butted spokes are a good solution, as explained above. The only downside I see is, during the maintenance phase (i.e. re-trueing) of a previously built wheel, the thin part of the spoke tends to twist (instead of the threads between the spoke and nipple rotating) when attempting to adust the tension. I have a recently acquired wheelset exhibiting this phenonemon. I may have to resort to completely rebuilding the wheels, if the threads between the spokes and nipples don't limber up sufficiently.