Besides Memorex, Verbatim and Sony, what would you recommend I try?
Try to find out discs that are manufactured by Taiyo Yuden or Mitsubishi/Verbatim, as they are generally regarded to be the best. From that it would seem that the obvious thing to do would be to buy Verbatim, but that isn't necessarily the case any more as they only manufacture some of the discs that they sell. The rest are from just about every other manufacturer out there, and it's not easy to tell which discs come from where although the Azo discs should be decent regardless. JVC discs are Taiyo Yuden I believe, and so were/are Maxell IIRC..