Well i have now been - while technically not unemployed - not working for 3 months.
It hasn't felt like a holiday, it hasn't felt like work, it has just seemed empty. I haven't accomplished a lot and despite having nothing major to do i haven't breezed through nearly as many books as you might expect.
Upsides: I have cultivated quite a healthy beard and a hermit-like lifestyle.
Downsides: I haven't really made any progress towards making money or working out what to do.
Part of me thinks this is a bad thing, i could have been working and earning and suchlike for 3 months. Heck even if i hadn't been doing anything financially beneficial i could have been doing something more traditionally 'constructive'. On the other hand i have spent a lot of time thinking about some important issues that would have come up sooner or later (a future post perhaps), so the time hasn't been totally wasted.