DVD's can store Films, TV Progs, Music, Photos, Data, Size = About 4.65 Gigs.
CD's can store Music, Photos, Data, Size = 650-800 Megs, (Films & TV Progs) need to be converted to SVCD or VCD to work on home DVD players, But they are not always accepted by the player.
DVD's come in 5 Flavours, DVD-R, DVD+R, DVD-RW, DVD+RW and DVD-RAM.
CD's Come in 2 Flavours, CD-R & CD-RW, But also 3 Sizes, 650 Meg, 700 Meg & 800 Meg.
DVD's and CD's Read all about them click here