Jetmonkey,
Your question, "A consumption-based tax would be nice, but how would you get the economy out of a recession or depression if fiscal spending was bound to consumer consumption?" is a very valid one, but as the consumption tax would be equal to a percentage of the purchase couldn't it be adjusted by changing that percentage? As most things are electronically connected it seems it would be easier than re-computing the methods of deductions, changes in Earned Income Credits, personal exemptions, and such. A simple update of an equation and it’s all done.