What is the best DVD recording medium?

Record on DVD-R for inexpensive one time recordings. Record on DVD-RAM discs if you need to re-record material. DVD-R discs manufactured by Maxell, TDK, Apple, and Sony have the lowest data error rates and best quality control. DO NOT get sucked into buying "unbranded" low-cost DVD-R discs. They are generally of poor quality and the recordings - those that actually work - show it.
ALWAYS record at the one or two hour record speeds. Recording DVDs at slower recording time speeds will yield discs which are generally unplayable on most DVD players.

Another word of advice. Though I did not mention it in my original post - I own a 13 year video editng and media duplication company. In just the past few months Phillips, Sony & Hewlett Packard have entered the DVD recording market with DVD+R recorders. THE DVD+R Discs they use ARE NOT COMPATIBLE WITH MOST COMMERCIAL DVD DUPLICATION EQUIPMENT. That means that if you put together an edited program and want to have it duplicated later on; most DVD replication companies will charge you an extra fee to transfer the DVD+R disc to something they can use for duplication BEFORE any duplicate discs are manufactured.
If you are seriously considering the purchase of a DVD recorder; I suggest you buy a Panasonic or Pioneer DVD-R/RW machine. All DVD-R discs made by these machines at 1 and 2 hour recording speeds are directly compatible with commercial dupliction equipment. And there are a lot more of them out there, In fact, Panasonic and Pioneer are already producing second generation DVD recorders.