lots of good feedback here already, but my $.02...
in my uneducated opinion, optical media is probably going to last about as well as you store it, no matter what the brand. if you have them rolling around loose in the back of a truck, doesn't matter if they're $10 a pop
aaton discs (not that they actually make them but if they did i bet they'd look sexy). similarly, cd-r's from reputable brand names wil probably hold up just fine if stored in cases in a drawer and not exposed to jostling/sunlight/dog mouths/beer spills/etc. in my experience, TDK cd-r's have never given me a problem and i can usually find them pretty cheap either online or in retail stores. dvd-r's i also like TDK, but my last purchase was unlabelled Ritek spindles and they are treating me just right as well.
as for the transfer, you could get a standalone cd recorder for probably pretty cheap these days, but then you have to sit there and insert tracks and babysit it. if you have a halfway decent computer, pick up a soundcard with a digi input (something that is bit-transparent - is that the term i'm looking for? - not the edirol units), a copy of wavelab or any other audio recording software that will allow you to program a pre-set recording length/time, hook up your dat to the pc and press play and record, respectively. lots of choices for soundcards, there are some usb options also. since it's dats you're transferring, you don't even need to worry about 24 bit, 16-bit and 44.1 or 48khz is all that will apply. once you've got the long WAV file of the dat on your pc, use cd wave editor to split it into tracks, then FLAC to compress it and burn those files to disc(s) for archival. many audio-cd burning software can convert the FLAC to cd-audio on the fly or keep a copy of the WAV files for burning audio cd's if yours doesn't.