Didn't realize this thread would turn into a good discussion. Couple of things I wanted to pass along for everyone to stick in the back of the heads.
1. Always check to see if your drive has a newer firmware available. New updated firmwares help with burn quality, error correction as well as optimize the lasers for specific media. You may have an 8x disc but the burner may only burn it at 4x. Updated firmware usually helps with allowing the burner to write at the discs maximum speed.
www.cdfreaks.com or the drive manufacturers webpage are the best ways to find updated firmware. It is easy, painless and usually only takes a minute or two. Those who are not technically proficient should not have a problem updating firmware.
2. If you are burning anything other than a casual disc like for archiving or even burning video ALWAYS burn at a slower speed. My personal rule of thumb is to burn at half the allowable speed. So if a CD will burn at 48x I never burn faster than 24x. A DVD at 8x, no more than 4x. The slower the burn speed the more accurate the burn and in the long run you'll be happier.
I think that burning coasters for the most part is almost entirely due to human error nowadays. The bigger current problem with faster and cheaper drives are the disc writing errors. That is entirely manageable with updated firmware and lower burn speeds.