For those that want to pick any of these comic books up (and help me out a little in the process), here are the links:
Showcase Presents: DC Comics Presents Superman Team-Ups Vol. 1
Showcase Presents: House of Secrets Vol. 2
The Savage Sword Of Conan Volume 6
Showcase Presents: Bat Lash
Showcase Presents: The Flash Vol. 3
Showcase Presents: Batman Vol. 4
Essential Sub-Mariner, Vol. 1 (Marvel Essentials) (v. 1)
Showcase Presents: Green Lantern, Vol. 4
I actually have several of the DC Comics Presents issues in my collection and I love the cover to the Showcase Presents edition.