@blogospheroid:
That's actually a very good question.
Financially, only a reasonable appreciation rate (technically, if you're an early adopter, you CHOOSE the appreciation rate yourself and can make it as big as you want; but if you do that, the next round of adopters will probably say screw you and start their own.). Everyone is different, but my threshold would be if something was appreciating more than 100% a year *above Moore's law*, I would say "screw that". Thus why I see 1M-fold increase in bitcoin and am basically saying, "screw that". Note I don't mean value relative to USD. I strictly mean the "coins issued per difficulty" value, which I would expect to be moore's law + 10% or so.
Admittedly the distribution of bitcoin is quite clever from an "incentivise early adopters" perspective. The problem, from my discussion with others about bitcoin, is it totally scares away the crucial "mid-adopters" you need before mass use. But perhaps I'm wrong and the price instability and difficulty increases won't scare too many away -- humans behave in all kinds of weird ways.
Would it not be in the interest of subsequent miners to increase appreciation. Say early adopters have mined 1M in one year. Secondary adopters with twice as much computational power decide on an appreciation rate of 500%. So after year two there would be 5M (early adopters) + 10M (secondary adopters) + 1M, and the secondary adopters clearly have more Hashcoins/power etc.
With the "inalienable rights" scheme the "tyranny of the majority" (in above example, or otherwise) would render Hashcoins impossible to function as "their" blocks would be accepted by the "majority", whereas "the minority" may not want to continue on those terms - or am I missing something?