I love monoprice, but the Wii component cables I got from them back in 2006 were defective (lots of pixelization and lines in the picture), as were the replacements. Probably just a bad batch though. After the 2nd bad set I just got a refund and bought the first party ones. But I've had great look with HDMI cables, optical cables etc. from the, so that's probably the best and cheapest option for decent cables. And I just had bad luck with their first batch of Wii cables back in the day.
Similarly, when I rebought a Wii in November I went with an off brand from best buy that was $5 cheaper and though the picture looked a little soft. End up returning those and getting the Nintendo ones. Did seem a bit better, but think it was mostly that the new Zelda just looks like ass on my HDTV.