I think you're assuming a lot here.
First, through personal experience I can tell you that the cpu does 'pause' for a signifigant fraction of each second(powertop will show that) when nothing's using it. Once you turn off the high-drain devices - wifi, modem and the screen - the N900's actually *very* good at saving power.
That being said, if an application goes crazy(hildon-home does this occasionally), the battery can drain in 4-6 hours. Also, if you *are* losing signifigant amounts of battery life in "idle" mode, look at your widgets: Poorly written widgets can easily half your battery life.

That isn't to say that rebooting takes lots of power - It does take some, though not nearly as much as BME would have you think.

Personally, though, when leaving the device on in idle mode takes less power than 10 minutes of use(as reported by batteryeye), I don't consider it worth the hassle of having to boot it each morning - Having it instant-on is *extremely* nice.