Totally agree with you about the Essentials. Great cost-benefit value, theolder stuff look AMAZING in B&W and you can find some seriously great stuff on those books. I think the Showcases are a bit trickier because Silver Age DC, IMHO, is a bit of an acquired taste, but even there you got things like Sgt. Rock, House of Mystery and other stuff that I think aged very well. (from jamesgf)
In some cases, I think the B&W makes some of those stories even better to read.