The key to designing a kitchen that is actually convenient for two cooks is to allow enough space for each to work without bumping into each other or competing for appliances and sinks. Larger kitchens that allow space for multiple work areas and can include an extra sink, oven, etc. are ideal.
Your design will probably need to incorporate more than one work triangle. U- and G-shaped designs are perfect because there is plenty of work space and enough room to create functional areas (like a baking center). If you want to comfortably accommodate two cooks, you will probably want to consider islands and peninsulas to create the work space you need.