One trick is to completely turn off the backlight (can be done on MBPs), and treat the display as a reflective screen. It isn't perfect: looks almost as washed out as with max brightness on the backlight, but without the battery drain.
Definitely an inspiring story with Balsamiq, though I do also see it as competition to Dabbleboard, so -ahem- you know where my loyalties lie.
If you don't need investors or cofounders/employees, there is no advantage to a startup hub. You could live anywhere with an Internet connection and a (VoIP) phone. In fact in such a situation it makes sense to live in an area with lower cost of living, as Balsamiq's founder is doing.
Cofounders exert a lot of peer pressure. I'd be surprised if being in physical proximity to other startuppy friends generally matters much, considering we do some of that interaction online (HN/Facebook/email/etc.) anyway.
Bologna is not a cheap place to live, although IIRC maybe he had some help with the apartment, which would be a big contribution. Italy in general is pretty expensive these days, especially considering the salaries.
Everytime I hear this guy's story, I get more impressed. He was actually one of the guys I had in mind when I wrote my post on why its a good time to be in a startup. Talk about capital efficiency!
I am a very happy user of Balsamiq. I was able to deliver 20+ rough wireframes in about 6 hours using its interface. It would've taken significantly longer in OmniGraffle and we've been able to use them cross platform b/c of AIR.
At an early stage of requirements gathering they're complementary for wireframes. Revisions/UI specs will be fleshed out in Omnigraffle for greater precision later, but that's after we've iterated with client in Balsamiq, which is what it makes so easy.