i found this info in an article on pcworld.com :
"What Are the Best Formats for Video, Music, and Data Discs?
As a rule of thumb, write-once media--be it DVD or CD--is your best choice for compatibility with consumer electronics devices, be it your high-end audio CD deck or your $50 Costco-special DVD player. Write-once discs have a higher reflectivity, which tends to make it easier for the devices' laser to read the data.
Use DVD-R or DVD+R for video projects. It shouldn't matter which you choose--although some players (Toshiba models, for example) don't officially support DVD+R, so it's a crapshoot as to whether the disc will play. My advice is to check online and see if you can find sites that note whether other folks have had success with DVD-R or +R on your player--and then go with that media. Long-term, either format should be fine for archiving; I believe both formats are entrenched enough that you'll find support for them long after your $50 player conks out.
For audio projects, pick CD-Rs. CD-Rs are the best way for you to create audio CDs, the format recognized by CD and DVD players. If you want to pack more music on a disc, convert your audio files to MP3 before burning them to a CD-R. But note that they're stored as data files, not as music per se. That means the player you're using needs to have a built-in MP3 decoder, as many DVD players and portable CD players do--but not car stereo and living-room CD players.
Burning music to a DVD is more complicated. Most DVD players cannot recognize MP3 files stored on a DVD, even though they can recognize MP3 files stored on a CD. And do-it-yourself DVD-Audio isn't available in mainstream burning tools. I've not heard any timeline for adding this feature, but I give advance props to the first software maker to allow you to burn two-channel audio to DVD. Just think of the greatest hits collections you could create on the fly!
For data, go with rewritable media. Rewritable media such as DVD-RW, +RW, -RAM, and CD-RW are best for backing up projects that are in progress. For example, you may expect to add data to a folder, or you're experimenting with different DVD menu design options before finalizing the disc; or you're performing a regular backup, and can reuse the disc time and again. Rewritable DVD is also good for temporary recordings; for example, say you're the sort who wants to record a Law & Order episode, watch it later the same night, and then record another episode the next day."
