My DVD player can't play R- so I use R+ for movies. For backups it doesn't really matter. If your writer can do double layer DVDs (9 GB) then you may configure your C drive in a way that fits on the DVD for quick OS reinstall.
DVD-Ram seems to be nice, if your writer suports it then you should use it for backups IMHO.
DVD-Ram seems to be nice, if your writer suports it then you should use it for backups IMHO.