Hey David, and welcome!
If you can find "Taiyo Yuden" media, these are pretty much 'master' quality media, and are reference media provided to optical disc drive manufacturers for testing. Considered by many to be the best on the planet. Be wary though, there are alot of fake TY discs out there, if you can find them make sure the provider is reputable.
Now, if you cannot find these (very hard to find in Australia, I know), look for Ricoh (under Sony +R brand) or Verbatim (Mitsubishi) media as these run very closely and some cases better than TY. The NEC you mention will try 'overspeed' these, so I recommend burning at the certified speed as per the package to obtain optimum quality, and minimal PIE errors (standard for measuring ECC on DVD medium).
As for + Vs. -, check: http://www.cdrinfo.com/Sections/Reviews/Specific.aspx?ArticleId=7664
Basically, +R media plays in the majority of DVD players out there bar a few older models. -R is more compatible than +R, but if you set the booktype to -ROM on the +R discs (the NEC can do this read review on main page), +R then becomes more compatible than -R.
DL media is tested and again Verbatim works very well, but is very expensive in comparison to +/- single layer media.
I recommend for your task the BenQ DW-1640 or Plextor 740A (same hardware, different branding or as it's called OEM) as this drive offers the upmost reading/writing quality straight up no complications/fuss or mess. If cannot find (these are only new on the market), NEC/Plextor/Pioneer/BenQ units will do the job anyway.
I adhere to the above 100% of the time. Trust me, you cannot go wrong if you follow this advise, you simply won't notice any problems, your DVDs will just play everywhere you chuck them.
Any questions, I'm right here