The boss came in this morning and sat down to ask my decision (the same one I'd tried to tell him over and over yesterday). This time, it stuck. I talked to the rest of the management team one by one, and everybody isn't happy, but they understood.
KatyaR - I am (or was) the HR person (one of two; I shared that duty with the CFO). This is a very, very small team. We fit the entire company staff into a conference room (EDIT: in our own small office, not at a rented space) a few months ago - we did have to put a few chairs against the wall, but, still. Very small. I wore many, many hats. Too many. They pinched. But that's what made it so hard to tell everyone I was leaving - I knew who would be stuck picking up the slack. I apologized, and they don't hate me. Much.
Late this afternoon I got a call on my cell, while I was on the phone with our finance guru, talking him off the ledge of my leaving. It was my new boss - I couldn't call him back right away, but I did email. The next couple of weeks, no, the next MONTH, is going to be weird.