Oddly enough, my DVD-Recorder(like a VCR...) supports DVD+R, DVD-R, DVD-RW, and DVD-RAM. It does NOT support DVD+RW. Strange huh? And it's even printed on the unit that it doesn't support this...
Personally, I tend to stick with DVD-R and -RW's. For the most part, they do seem to be the most compatable with other drives. However, I have seen some drives that can only read "+" media...