Cables will affect your tone. More so over long distances than short ones. Most of us couldn't tell the difference, though. If you can find cable made from mogami, those are supposed to be best, but can cost you a lot of $$.

Planet Waves has some good quality cables at reasonable prices. And I'm thinking... until you can answer your question for yourself, I would not bother spending more than $20 or $30 'cause you won't hear the difference anyway. :)