DVD -R or DVD +R

+R's seem to be much more reliable and problem-free in my personal experience and in the experience of half a dozen or so of my professional IT colleagues. Deep in the gory details (see Lkdog's links), the +R's have some technical superiority over the older and more "official" -R's. Most all units these days, both computer and consumer audio/video will read either equally well. I moved from -R's to +R's early on (2+ years ago), and my professional colleagues at work have done the same (both for data and video) - we've simply found them more reliable and trouble-free.

DVD-R's are seen as compatible with more set top units.
Most computer and standalone burners will record both, but I would use DVD-R's.

Here are a few sites that might be useful to you:

http://www.dvdhelp.us/
http://www.dvd-recordable.org/index.php
http://www.cdfreaks.com/

Just 2 competing formats. They both work equally well. -R may be slightly (5%) more compatible since it is a year older. If you're just burning data then it isn't much different than burning a CD-R (except for 7 times more space). I would be more concerned about the quality of the discs rather than the format. Use discs made in Japan if you can find any.

-Rs are the only DVDR sanctioned by the DVD commitee or whatever you call them. DVD-Rs seem to play in more machines also but with newer devices, they both seem to work equally well.