I no longer know what is hot, but if you are suggesting cards Pre 1960.
It is kind of like collecting stamps they are making so many of them everyone has them, so you have to go back to about 1930 and start collecting backwards.Its like sports cards go back to 1970 or 1960 and start going backwards and buy the most exclusive cards you can afford.With the economic situation the way it is there may be some pretty good deals out there.