I've yet to have a CD-R fail on me. I still have the first CD-Rs I burned, which would've been close to four years ago. Any manufacturing defect should show up in the first year. There have been instances with Dual Layer DVDs coming unglued due to manufacturing defects, though that wouldn't affect DVD-Rs. I haven't had the DVD+R long enough to know anything about longevity.
Good advice on the combo drives...the only problem is they are the most expensive ones. f you dont mind the extra cash, thats the way to go. I agree with mr Paige abou the longitivity issue. I never buy cheap media, only good name brand ones for me(verbatim, Memorex, etc..) and I still can read and use CD-rs that I burnt with my old 1x cd burner. I would expect the same from DVD-Rs, the only problem with alot of the geeks at places like Slashdot and DVDRHelp is that they go thru soo omany discs, they love to buy the cheap, large spindels of no name media..so Im not surprised that they have problems with em. I have had my burner less than a year, so I cant speak for how long the media lasts, but I am willing to bet it will last just fine. (Im betting my data...)