Welcome to the forum!The Sony 500A is the best current drive,but is pricey.It does both formats..Dvd-&Dvd+.The current trend is to create dual capable drives.
That said,The Pioneer A05 is a good economical choice.It only supports Dvd-r,but will probably outlast any changes to the formats war.Dvd-r media is also much cheaper in most places in the world.There firmware hacks out that make the Pioneer quite a good buy.Either drive will do what you need.