- DVD5 Media Verbatim DVD-R or Verbatim DVD+R
- DVD9 Media Verbatim DVD-R DL or Verbatim DVD+R DL
Also note that not all PS2 lasers handle DVD+-R DL discs very well if at all, often it is beter to look for DVD5 rips
There are some none Verbatim branded media that do work just aswell specially DVD+R media
Infact most + media will work - media is a littler harder to find quality media that works on the PS2
Dual/Double Layer media is very hard to find good quality none Verbatm media
Recomend you just stick to Verbatim DL media for your DVD9 games if you can play from DVD9 backup's at all
If you are thinking of buying a cheaper discs though check out
Video Help - DVD Media first and find the DVD's you want to buy there, this will provide you with good information including Console reliability