Just a quick answer with a question...
For the straight DVD -R, +R, -RW, +RW response, I don't think there's much difference these days, most drives and readers support everything.
But what do you want to use them for?
Playing in a DVD player to a TV? Sharing with friends straight to their PC? Or for achival/backup?
Playing in a DVD player to a TV, what you want is highly dependent on the player. If it's been made in the last few years, most formats and disc-types should be OK, just burn the files straight and the DVD player should navigate and find them. For aything older, you may have to go to PictureCD or other similar weird styles, or make a movie/slideshow, and hopefully someone else can help you on them. Maybe check with your friends as to what their players support first...
(and if they've got relatively new TVs, or even set-top boxes, a lot of them take USB drives too)
Sharing with friends on PCs? These days, it may be sad but true, that you're more likely to find a USB port than a DVD-drive on a computer. Uber-lightweight and small netbooks, iToys and the like, they all started ditching Optical drives a while ago.
Archiving? Don't even think about it. I've read (and i'm sure you can google your opinions too) that the dye in the recordable-layers on dvdrs doesn't last that long, maybe 5-years tops. Stick to USB drives and external hard discs for backups...