Currently reading Design Patterns by Erich Gamma (Author), Richard Helm (Author), Ralph Johnson (Author), John M. Vlissides (Author) (aka the Gang of Four).
Its amazing coming back and reading this book again after so many years. I remember the first time I read this in 2002 having alot of this gloss over my head and now many of these design patterns are second nature – I couldn’t think of designing any type of OO software without these patterns.