I can spill the beans now: like many other folks on here, I'm onto a new job. This was an extremely difficult decision, since I was one of the founders of the company I'm leaving. But working at home, by myself, all the time, proved too much to bear in many ways.
Concidentally, with the recent notes on here from graydon about taking things easier (on ourselves, the earth, etc.), one of my primary motivations is taking things easier. For me, working at home really taxed my ability to separate the work and non-work areas of my life, and the balance between the two (never right to begin with) got seriously out of whack. It got so that I felt guilty doing something (even nothing) for myself -- just watching TV or going out camping for a weekend or whatever. This is no state to be in, particularly for someone who just got married.
I recognize that I work in an industry -- programming, web development -- that relies on people enjoying their jobs and not putting up much of a fuss over working 50-60-70 hour weeks on a regular basis. Occasionally, this is unavoidable, but IMO it shouldn't be the norm. Work should be a means to an end, not the end. IME Europeans seem to have a better attitude about this than Americans do, but that's neither here nor there.
Of course, another huge motivation for taking this job is working closely with other technical people. I recently learned what it's like to work closely with someone over an extended period of time, and I don't know that I can ever go back. Even if your comrades aren't at the same level as you, having someone around to interact with raises everything to another level. (Plus might get lucky and enter into a teching relationship as either the mentor or the student.) This might be a failing on my part, this relying on face-to-face contact for certain things. But I'm not trying to generalize my experience to everyone else, either :)
That said, I'm interested to hear from people who work by themselves all the time how they deal with it, or if they even have anything to deal with. It might be that my previous experience working with someone was a fluke because he's an exceptional person, and that I'll hate working with people and want to go back to working at home in my sweatpants with only the cats to talk to. We'll see.
(Originally posted elsewhere)