I would not suggest the Apple forums,
for the reasons outlined here. A lot of the blank disc posts there give generic advice like "try another brand" or weird/untrue advice like "gold discs work best". That's not good, it shows a lack of understanding of optical media. Good forums, good information ... just not necessarily on this topic sometimes.
OS X, Linus, Windows computers, non-OS DVD recorders -- it all works the same, as far as the burner and media goes. Same manufacturers, same basic processes.
Memorex is a generic brand that re-brands media made by other manufacturers. Some of it is good, but most of it is not very good at all. Just cheap stuff that gives a majority of people problems.
If this is the same Pioneer 106 drive discussed in the other thread, you should look for older 1x-2x media, don't try to use 4x discs. Assuming you're in the USA, Walmart and Walgreens commonly has both in stock. Sony DVD-RW should be fairly easy to find, and I would suggest it. Verbatim, Maxell and TDK, from the 1x-2x generation, can be found here and there too, and those would work well for you. There may be some stores online that stock it too.
Amazon.com has
I personally use Pioneer 2x, TDK 2x, Maxell 2x, Verbatim 2x and Sony 2x discs, in older burners/recorders that only want 1x-2x DVD-RW media. I've had the same 40-50 discs for 4+ years, many good uses/re-uses, with weekly to daily use.