I am of the opinion that it is not a good idea to cheap out on cables. Will it affect audio? Almost certainly not, but dealing with crappy connectors or a bad termination is massively annoying. As much as anything, I like high-quality stuff and cheap cables don't feel high-quality.
I make all of my own. For XLR / TRS, I use Canare L-4E6S. Neutrik for XLRs, Amphenol, Switchcraft or Neutrik for TRS. Van Damme cable is excellent quality as well.
For RCA, Canare GS-6 with Neutrik or Amphenol connectors.
For my test bench, I make XLR / TRS cables out of the inside of an old Canare mic snake. It's similar to Canare L-4E5C. I like it because it's thin and flexible. For RCA cables on the test bench, I use RG-174 coax. Works well enough.
Also, if you're building or modifying your own gear, do yourself a favor and buy some Mogami W2944 "Console cable". This is very thin and flexible- it's the kind of thing that you'd use if you were hand-wiring a mixing console. It's an excellent choice for shielded cable inside a chassis and is easy to cable manage.
IMO, if it's good enough for a high-end recording studio it's good enough for my home stereo.
