There have been several posts about this topic in the past; and it might be worthwhile to look them up. I own a commercial media duplication company and we've not only copied thousands of CDs and CD-ROMs, but even more DVDs. Generally speaking, slower burn speeds equal cleaner results. I duplicate most of my personal discs at 2X speed on a dual well Marantz professional CD recorder, and have never had a disc that didn't sound great. As for media types, we have used a lot of Maxell, Mitsui, and Sony CD-Rs with good results. Though we mostly use commercial grade discs; we've consumer stuff in a pich with good results.
As discussed above, don't waste your money on "cheapie" CD-Rs. Many are rejects from major disc makers that didn't pass quality control at the factory. Good luck!