It's good to hear from others who think in the same way-
I moved to a new job last year where there were no fixed hours (my previous job required that I should be in at 9am). This alone made me feel like I was going into the office because i 'wanted' to, not because I HAD to... Ironically I still end up going in for just after 9am everyday anyway, but that sense of freedom leaves me feeling so much happier on a day to day basis!
I used to work at a company that had no fixed hours... I usually spent at least 10 hours a day on the weekdays and often stopped in on the weekends and there was usually at least a smattering of people there, and collaboration and morale were both high. They really got it right on that one. Then investors started courting the company, and management started telling people they wanted butts in seats at 9:30am. Well as soon as 5:30 rolls around it became a ghost town.