I would actually recommend that you look closely at moving your whole design to the 3.3 volt realm. It is the way of the world today. It is fun running the scope at 1 v/cm instead of 2 v/cm.

All well and good, but your noise margin decreases. For instance, some of my stuff is mounted directly under fluorescent tubes and I do not have a ground, only chassis. I need every bit of noise margin I can get.

Erik