What kind of soundcard/motherboard do you have? What kind of receiver do you have?
If the receiver is better than your sound card/device, you will want to use a digital S/PDIF line so the receivers DAC's to the digital to analog conversion, and if your soundcard is better then your receiver you will want to use a standard 3.5mm to RCA analog cable.
Optical is virtually immune to environmental noise, but otherwise it's the same data being sent. Also the coaxial cable topology is itself designed to be pretty noise resistant, so in most cases if there's enough environmental noise for there to be any meaningful difference between the two, you're doing it wrong.
I use optical because then I don't really have to care about routing or cable quality or any of that, but I also have the connections available and long, straight runs between my components. For shorter, less direct runs you pretty much have to use coaxial since fiber optics aren't nearly as flexible as copper wire. Sound-wise, there shouldn't be a difference, but sometimes one is more convenient than the other, or sometimes you only have one sort of connection available. But there is absolutely no "optical will sound best" involved.
also, why wont it last long? its copper and something that I suspect to be tin/aluminum/lead wrapped in a plastic goo
I don't think you can really break that unless you sever it somewhere, or you're in an environment where the pressure/heat constants are extreme enough to do screwy things (like superconduction or sublimation)