The first thing I had to look at, when I read the title of this thread, was how many posts the OP had... figured it HAD to be a newbie!

We all went through a stage of asking this question (and some of us have never stopped asking it

), and while it may be hard to find the threads with a given search engine or search words, there is a LOT of discussion about it, going back for years, not only on AK but also all over the web!
Anyway, cables CAN make a difference, although beyond a certain point, you need a very good, revealing system to be able to hear the differences.
The law of diminishing returns does set in at some point: you don't have to spend a LOT of money to get GOOD sound on MOST common audio systems.
Check out the DIY cable threads for ideas on how to make good-performing cables at much lower cost than their ready-made counterparts in the audio stores. Mogami and Belden cables are often used in these, and which jacks you can use depend on your budget and preferences.
Alternatively, "pro" cables are often cheaper than "audiophile" cables, but have broadly similar sonic quality characteristics; they probably tend to offer the best "bang for buck".
While you don't have to spend a lot on cables, avoid the really cheap ones such as the ones included free with most gear, or sold in drugstores, supermarkets, etc... They ARE bad.
A/V or video cables, like the 3-wire and 5-wire ones 70salesguy was talking about, are often great value-for-money. In order to carry a video signal well, they need to have certain characteristics, and these often work out well for audio cables. But the prices are generally lower, since most people hooking up their HT A/V system are not willing to pay an "audiophile" premium. Also, they are mass-produced in MUCH higher numbers than 'audiophile' cables, which helps keep their prices down. If you have an old turntable in your system, you'll probably want to read about "Petra" cables, which fall into this category.
That's as much as I'll say here, since this topic has been beat to death by many (including myself) before, in many threads. Search some more, and you'll find plenty buried around. It's an age-old controversy in the audio field.