Some good recommendations above. Some can be auditioned with a return privilege (TelWire for example).
IMO, it's best to stick with brands that have strong demand so re-sale is easier. Shunyata, Purist Audio, Transparent, Cardas, Audience, JPS Labs, Kimber, etc. (this list is not exhaustive by any means). Take a look at the classifieds and you'll see which brands have the most for sale.
6Sons Audio in Canada makes some good power cables. They might offer a home trial.