The relationship between system condition and SNR in reconstructed Stokes parameter images is investigated for rotating compensator, variable retardance, and rotating analyzer Stokes vector polarimeters. A variety of optimal configurations are presented for each class of systems. The operation of polarimeters is discussed in terms of a 4-dimensional vector space, and the concept of non-orthogonal bases, frames, and tight frames are introduced to describe this class of devices. While SNR is an important consideration, performance of a polarimeter in the presence of systematic error is also important. Here, the relationship between system condition and error performance is investigated, and it is shown that an optimum system from the point of view of SNR is not always an optimum system with respect to error performance. Finally, the concepts used to optimize Stokes vector polarimeters are extended to be useful for full Mueller matrix polarimeters.