I've done some testing and conclude whatever you choose effects the sound. Of those available aftermarket, assuming you are not buying completed factory terminated speaker wire, Cardas is among the best known and George makes a very fine product.
I've also had good luck with Vampire Wire connectors, especially their copper binding posts but I don't know if they still offer wire terminals for DIY. Cardas "parts" page on the WWW shows their current offerings.
Hopefully someone else can toss in additional brands based on their experience.