Cables definitely make a difference, but over short runs those differences are typically negligible, and high quality buffers make those differences even smaller. The most important cable in your set-up is the one that connects your guitar to the first input, as it "handshakes" with your pickups, so you'll find the greatest differences when swapping this one out. Also, one of the best skills you can develop as a guitarist is buying bulk cable and getting decent at making your own--as it can cut down cost by 50-70%!
For most of the music I tend to play and produce, my personal favorite is Belden 8412. The downside is that it's rather expensive, not terribly pliable, and the external wrapping tends attract a lot of dirt and dust, so those usually stay away from gigs and are reserved for studio work only.
For all other applications, I find Mogami W2524 to perform extremely well in terms of sound quality, workability, flexibility, and durability--and can be found for less than $1/ft. For mini leads on my wireless units, Mogami W2314 has performed similarly well. Be aware though if you're thinking about making your own: some fantastic-sounding cables out there have braided internal shielding (BTPA and Gepco come to mind) that make terminating them a bit of a chore.
Mason from Vertex Effects has a couple excellent videos on the differences between cables. Consdier checking them it out!
