Essential Ghost Rider Vol. 1 and Essential Werewolf by Night vol. 1:
During the 1970s, when the Comics Code was loosened a bit, allowing for more "horrific" approaches to comics and superheroes. Marvel began experimenting fairly heavily with the super-hero/horror genre because of this, and while some iconic characters came from this period (Blade, for instance), most of the experiments from this era have been relegated to guest-star or forgotten status. Some of the titles included: Monster of Frankenstein, Werewolf by Night, Tomb of Dracula, Ghost Rider, Son of Satan - and a few others. Of these, only Ghost Rider and Tomb of Dracula had any real "staying" power. The others lasted a while, but only those two titles lasted beyond the initial "strange" period Marvel had during the late 1970s.
I gleefully have all FOUR Essential Tomb of Dracula comics on my shelf, and these two add to my collection of horror comics. I have to say that the B&W format of the Essential Books adds to the horror element of these titles (though that's not to say I wouldn't mind a full-color version as well).
One fascinating aspect of these "experiments" comes from the way the characters shifted so often. In Ghost Rider especially (but also in Werewolf by Night) a constant bouncing back and forth between tormented soul horror stories and basic superhero tales. The writers seemed unable to achieve any real mixture of the two, opting instead for tales that were clearly one or the other.
Either way, Ghost Rider still rocks. I, of course, have all the original issues reprinted here (and am mystified by the exclusion of an early Marvel Team-up appearance that introduced GR's early main archnemises, Orb), but these tomes allow me to revisit the early tales without having to dig out the old longboxes.