Personally I wouldn't recommend Ritek, I've had nothing but bad experiences with them.
Taiyo Yuden are the best out there but you probably won't find them locally, you'd have to buy them over the net.
One thing to understand with Blank DVD media is that Brands such as DataWrite, Verbatim, RiDisc, etc. are only brand names they do not make the DVD's. So you could go out and buy three different brands of DVD but still end up with them all being the same (made by the same manufacturer).
When you look at brands of DVD's on the net some of them will state in the description or info that they are Taiyo Yuden, or will have an abbreviation such as TYG02 listed as the Disc ID. You'll get the hang of it if you read some of the other threads on this forum.
Hope this helps.