You'll find yourself being a night owl again in no time. Its just a lot less distracting, and you can be a LOT more productive.
Also either get better lighting...or turn it off completely. What you have now is very depressing, and will take a toll on your productivity once the initial high of doing a startup wears off
we moved to london to be in the center of the advertising community, which is working out well. been there about 4 months now (i can confirm that it's always raining here).
This is what is so fun about a startup - never an empty to-do list - and they're always new challenges.
I envy your full-time position and dream of that day myself - keep up the good work!