Elasticity of Durable Goods vs Non-Durable Goods
For the theory, House (JME several years ago), Barsky, House and Kimball (AER, circa 2006) Barsky, Boehm, House, and Kimball (working paper on SED website).  Johannes Wieland has a new paper on this, maybe not yet available.  

The key theoretical point (put somewhat loosely) is that purchases of an "idealized durable", one with a very low depreciation rate, should have a near-infinite intertemporal elasticity of substitution.