This is just my humble opinion, of course, but the most compatible format is DVD-R right now. It has the most readability of any format in standard DVD players of any other writeable/rewriteable DVD format. They're hacking out new formats all the time, so who knows when it'll stabilize...
By the way, when I spec'd my friends video editing rig, I told him to store his old SVHS videos in MPEG-4 DivX format onto CDs. At 1500kb/s, you can store an hour of video per CD, and FlaskMPEG splits the files into one hour chunks during an encode. DVD would've been nice, but the price of DVD blanks and drives is still prohibitively expensive. The format fuss also doesn't help, but at CAD$20/pop, DVD-R blanks are NOT the way to go for now.