Ati, you've got me thinking.
Although I'm extremely happy with a biphasic routine (for the same reasons as you - more refreshed etc), I'm always keen to tweak things a bit and further improve the routine. In particular, the idea of getting up at 3:45 sounds great - nice and quiet throughout the house, so I can get plenty of work done before the rest of the world wakes up
Next year is looking to be off to a great start. Let the experimentation begin. Have a great Christmas/New Year (I'll be away for week or so). See you all in 2007.