One of the best sites i have ever found on Software patterns, anti patterns and refactoring.
Sourcemaking Patterns Antipatterns and Refactoring
Well thought out and with lot of common sense.
Especially, Death-by-planning AntiPattern is very good read.
If you are into Software project management please read more of Antipatterns.This give good insights on common project management pitfalls.
if you are a programmer,designer then Patterns and Refactoring is for you. It somewhat resembles Design patterns by Eric Gamma et al.