Any tips on how I can I design an integrated IT/Business strategy that is flexible enough to change direction in response to external influences, but stays aligned?
This question is very broad and general. The answer is going to vary on many factors such as the culture and values of the organization. Depending on the goals and business drivers, the "strategy" may involve cloud, social, or mobile technologies.
If I make an assumption that you are talking about solution delivery methods, since this is a Rational forum, then again this will vary greatly on the context and culture in which they are applied. This is why I advocate an expert system called the Software Development Practice Advisor. Based on context and culture inputs, SDPA will provide advice on which IT practices to use for PPM Governance, Alignment / EA, Acquisition, Development, and Service Transition. The system learns as you learn and allows teams to change their process at the end of any iteration or sprint.