Align between guides option
The option to align between the two closest guides would help greatly when working on a multi-column document. Currently the only way to align to a single section of an artboard is to draw a box and align to that. Aligning to guides would streamline that quite a bit
Jeff, I believe you can do this if you unlock and select guides... but it also requires all objects you want to align to be between these guides also... but the same it trues for guides-auto-picking you propose.
Have you tried this method? Does it work for you?