I did Devil Hunter Yohko (which originates from 1990!) which is probably my most well-known old school cosplay. Now that I think of it, I suppose my Android 18/Juuhachi Gou cosplay from Dragon Ball Z counts too! That anime premiered in the late 80s/early 90s. :D
I have Misa Hayase from Macross planned, which will definitely be my most oldschool anime character cosplay. It was planned for this year's AX, but is unfortunately being postponed due to a few reasons. :(
Oh yeah. I did a really ghetto Fujiko Mine with my friend as Lupin once, haha, but I barely count that one!
Yohko: http://images.cosplay.com/gallery.php?cat=64470&member=31
Android 18: http://images.cosplay.com/gallery.php?cat=25474&member=31
Fujiko: http://images.cosplay.com/showphoto.php?photo=156299