@buzzard7 - no disrespect on what your speakers came with. I made the completely invalid assumption that everyone had at least heard of Monster.
But for those who haven't, they sell audio cables. They make a lot of advertising claims about how their wires make your system sound and have sued many many people for many reasons, all of which seem totally spurious. I have seen no convincing evidence that their cables actually do anything to improve the sound. My own belief is they're basically an aggressive marketing company, long on the legal department but short on real R+D.
The underlying reality of audio experience is that the best human hearing tops out around 20Khz (in children). In adults it's markedly lower (mine is 12Khz, not bad for my age). The Nyquist criterion states that to properly sample a signal, you need a sample frequency equal to twice the highest frequency of interest - hence 44Khz for CDs. In electronics terms, this is not very high at all (your microprocessor is running about 100,000 times faster, just for example) any modern amp will have a perfectly flat response curve that goes far higher than this. Further, due to the non-linear response curve of the ear, ADDING noise can increase the detection threshold for faint signals, which in turn increases the perceived loudness and influences the perceived quality of the sound.
Hence some people prefer vinyl, some people prefer tube amps, some people swear by this system or that system. However none of this makes "different" into "better" and "more expensive" is so vastly different from "better" that it isn't funny. Room interactions are well over half of the sound quality puzzle, and most people don't even know those pieces exist (and there's a limited amount you can do about it unless you want to build your own audio booth)
You need...
A decent signal. The main issue for a soundcard is keeping out transients, but most do this OK.
A decent amplifier of sufficient power to run your speakers. Anything built in the last 30 years will have a flat response curve.
Decent speakers of sufficient power to usefully use your amp. You need to be able to handle the power at each frequency.
That's all. Having fancy high end gear (cables included) is like having a fancy high end car. It looks cool, but when you're commuting in traffic, is all that top end performance actually doing anything for you?
Other than attracting babes, I mean.