DVD standards are a minefield, particularly when it comes to rewriteable formats. The problem has been caused by the existence of two rival factions: the DVD Forum, which promotes the DVD-RW specification; and the DVD+RW Alliance led by Dell, HP, Mitsubishi Chemicals, Philips, Ricoh, Sony, ThomsonMultimedia and Yamaha. DVD+RW is in some respects technically superior, but the market will decide.
However, a couple of recently announced drives look set to change the landscape significantly. Sony is one of several companies with a foot in both camps and has decided that consumers aren't interested in waiting until the politics are sorted out.
In September it announced the DRU-500A (internal ATAPI) and DR-500UL (external FireWire), multiformat drives that offer full compatibility with both DVD+R/RW and DVD-R/RW media. Costing around £280 (inc. VAT), the internal drive is available now, with the external model expected to cost about £40 more. If these drives live up to expectations, it could mark a significant turning point in the format wars.
Meanwhile in the DVD Forum camp, Panasonic is planning to launch (early 2003 is the best information I've managed to obtain) the DVD Burner II (SR-8588-C). This will be the first drive to support the new DVD-Multi specification, which covers DVDRW, DVD-RAM, CD-RW, CD-R and DVD-R media in addition to all standard read-only CD and DVD formats such as Video CD and DVD-Video.
The DVD+RW Alliance has no comparable multi-format specification (as it has no rights to DVD-RAM), although a DVD+RW drive will read and write to DVD+R, DVD+RW, CD-R and CD-RW media. It won't read or write to DVD-RAM, DVD-R or DVDRW formats. My money's on Sony's approach, as simplicity is what everyone wants. The lack of DVDRAM support is a bit of a nuisance -- although it's nota particularly popular format despite its great suitability for backup and archiving purposes.
If I was building a new system and had the money, I'd go for one of the Sony multi-format drives plus a Panasonic DVD-RAM/DVD-R burner (the current LF-D311 costs around £330 inc. VAT). This would cover all bases, although it would cost you around £613. If Panasonic's new drive achieves the predicted sub-£300 price point, it would be slightly cheaper to go for this in combination with a £200 DVD+RW drive.
At least the choices are becoming clearer, which is exactly the way the market should work.