I use 16 gauge lamp cord on my M50s. I use big honking Canare Quad Star on my M80s. Why? 'Cause I wanted to.
I have to agree with Amie. I spent a bit more for cables because they are audio jewelry. If i have to look at them, they may as well be pretty, albeit reasonably priced at least.
I went less expensive with the speaker wire but got some lovely quality stuff for about 50 cents a foot. I would say 50 cents Cdn, but since that equates to more $ for the Americans now...it only sounds more expensive.