Lets talk about cables.

I would like to know what you all think about cables. Specifically interconnects and speaker cables. I have built myself a modest system that i am currently quite happy with. It consists of a jolida 100wpc hybrid integrated amp. Vanderstein 1bs and a rega dac. I am currently just using basic radioshack interconnects and speaker wire. I just wonder if i would gain a noticeable improvement if i were to invest in some better cables. I would love to hear from someone who has actually done a/b comparisons and if there was a discernible difference. I am not interested in hearing from someone who just wants to shout about them being a ripoff without having ever taken the time to test it out.