http://www.interfacebus.com/Design_Logic_Family_Selection.html
I just found a web page that has useful charts comparing the various 7400-series “TTL” Logic Families based on different aspects such as power, cost, voltage levels, where are they on the curve from new to obsolete, etc. So if you are overwhelmed, like I am, by the choices that we have today (74LS00, 74ALS00, 74AC00, 74AHC00, etc.) this page may help you sort them out and decide what you want to use for a project.
Other pages on this site describe design pitfalls to watch out for and the passive components (R, C) used in digital logic circuits.
http://www.interfacebus.com/Logic_Design_Descriptions.html
Does anyone else have a favorite web page or book that they find useful?