  The Goldstone mode due to stripe or unidirectional charge-density-wave order
in electron systems is found to have the same functional form as the one in
classical smectic liquid crystals. It is very similar to the Goldstone mode
that results from helical magnetic order. This allows for an effective theory
that provides a quasiparticle description of either stripe phases or
helimagnets in the low-energy regime. The most remarkable observable
consequence is an electronic relaxation rate in d=2 that is 1/\tau ~ T\ln T in
clean systems and 1/\tau ~ \sqrt{T} in weakly disordered ones. The
corresponding results in d=3 are 1/\tau ~ T^{3/2} and 1/\tau ~ T, respectively.
