I'm in this for the long haul. Holding all my coins except the ones I sent to BFL for ASIC.
I don't associate selling with not being for the long haul.
What if all miners will hold all the coins mined ? I believe that it will help the Bitcoin economy and Bitcoin adoption if a percentage of the coins mined are "released" into the market. Via exchanges to USD, via sales in BTC, via gifts, whatever.
That is a very legitimate point and I think you are correct that coins need to move around in order for there to be more wide-spread adoption. If I see a service/product I find value, I'm not opposed to using coins to buy it. But, I'm much more in a saving mode than spending, so it would have to be something very good to get me to use my coins right now or in the near future.