Thanks for all the work you put into the DVD media FAQ. It was very helpful to me. Please spend the 3.7 cents you made because I used your link to buy a stack of Taiyo Yudens wisely ;-)
A suggestion for something I think should be a FAQ, but doesn't seem to be: do you (usually) get better quality recordings if you burn at less than the maximum rated speed? E.g., burning "8x" media at 4x.
Part of this is actually answered on the "Advanced Concepts" guide on the site: http://www.digitalfaq.com/media/advancedconcepts.htm
In general, in the year 2009 (and for the part couple of years, actually), it's been suggested to burn at, or just under the "rated" speed of the media.
On your typical 16x discs, you'll get the best results from burning at the 4x-12x speed range.
Too fast is just as bad as too slow, so 1x and 2x may be just as bad as "full blast" 16x burning. Burning beyond the rating of the media, such as 18x-22x is not suggested. Overspeed burning has NEVER been suggested, since the early days of when people tried to burn 1x media at 2x speeds.
This topic can get really picky, and it does get affected by the drive in use (more so, in fact, when dealing with DVD+R DL media burn speeds).
This information, of course, mostly affects computer-burned media. Discs burned in DVD recorders (set-top machines that have replaced VCRs) are burned with a different method, it's realtime, below 1x speed. These burns tend to be fine, but it all comes down to the burner inside the recorder, and the quality of media being used.
Verbatim and Taiyo Yuden 16x media work best in the 4x-12x range.
Remember that 6x is the fastest "continous" speed allowed by a drive (not all drives have this speed, either), and 8x and faster are "zonal" burning, where speed ramping is used either in a stair-stepped zone system (Z-CLV), or as a gradual increase of speed (PCAV).
Remember the speed differences (when burning a full disc):
1x = 55 min
2x = 30 min
2.4x = 20-25 min
4x = 15 min
6x = 10 min
8x = 7-8 min
12x = 6-7 min
16x = 5-6 min
18x+ = ~5 min
High speed burning has a high risk of data fail (bad burns), but you only pick up seconds at most, under a minute, once you starts to surpass the 8x speed range.