My view is every little helps - but it's less important thn a good amp, great pickups and guitar. There's a huge difference from cheap £5-10 cables up to £20 Planet Waves, Whirlwind, George L, after that it gets subjecive.
If you've weaked your setup amp, fx and guitar to the max, then it might be time to think of cables and the mains you use. If you're not at that point try the three above and see if you can hear a difference, and go with what you prefer. I like the bright lively quality of George Ls, but that's not to say you will!