If there is not a difference in the sound of various brands/prices of cables, then why wouldn't we all just use the cheap stuff and invest more in music? One reason would be the "snooty" factor of liking the "idea" of having the high price spread in your system. Another reason why some invest tidy sums in cables is that in their system and circumstance they hear a difference that justifies, for them, their cable investments.
My cable purchase decisions have been based in part on reviews, price and most importantly, experience over decades in audiophiledom. Please know that I, in that time period, have made some significant purchase errors. Fortunately, most of those mistakes were rectified at little financial detriment.
Interconnects - I like the Audioquest line because of many years of experience with their cables and that whatever their current line is, their is a consistent sound revealed by their interconnects as you move up and down the line. The trick is finding the cable that best suits your sonic tastes with your system. Example. I tried AQ Columbias and Colorados from the line previous to their most current offerings. In being able to A/B them, the Colorados had a fuller more natural bass response than the Columbias. Their response sounded to me to be very linear up and down the frequency response of my system. Therefore, my system is wired with AQ Colorados.
Speaker Cables - Here is where I learned a new lesson a little over a year ago. When I traded in my Vandersteen 3A Signatures for Treo CT, the copper heavy earth series AQ cables that I had used successfully with the model 3s sounded too heavy in the mid-bass with the Treo CT. And yes, I experimented a great deal with speaker placement trying to find a spot in my room to tame the mid-bass beast. Didn't happen. Then came research time. I was reading hours each day all over the internet, investigating cables from myriad manufacturers, many of whom I was completely unfamiliar with.
It was in this forum however that I began reading more and more about Paul Laudati's Clear Day Audio cables. The more I read the more the adjectives used to describe the sound people were getting through them started to sound like what I was looking for. Next step. Call Paul. That I did. He was very forthcoming with information about his cables but made no wild promises about how they would do with my system. The price was very reasonable for what he was offering and so I took a leap, after even more research and purchased the Double Shotgun models. Fortunately for me, the mid-bass hump was gone and the treble smooth but opened up so for the first time I could truly hear what the CT tweeters were capable of.
In summary, experience, research, personal contact and anecdotal information from others informed my choice here. Isn't that what a lot of us learn from other's experiences here on this forum, kinda the whole point of spending time here. The bonus is of course, in those situations where sharing your audio travels can help someone else here on their journey.