PS2 is not that fussy on CD-R media for backups. I use cheapest CD-R media, pop it into my v5 PAL (Messiah) and it boots fine.
For DVD writers, there seem to be 2 big boys at the moment - the Pioneer (either A05 or A04) and the Sony DRU500A.
DVD-R & DVD+R difference has been answered a few times before, read back on this forum for a bit and you will find your answer.
DVD media for PS2 backups - many on this forum use Traxdata DVD-R.
If you are in the UK
www.bigpockets.co.uk or
www.blankdiscshop.co.uk for media and writers.