Regarding the transaction fees, it is indeed difficult to determine what will happen, but if they aren't high enough to provide incentive for the miners, then they won't go through. Funny thing that.. we may end up mining not because of the transaction fees but because failure to mine means our existing bitcoins may become worthless.
No one will mine with transaction fees not at least equaling out to the amount of money via electricity going in, and therefore simply will not accept tx fees below a market set amount, which will cover costs + profit. Only the small minority with "free" energy will be able to afford not to do so, and eventually I'm sure landlords, business owners etc, will all wise up. Mining farms will be centralized near the cheapest sources of energy. Holy conspiracy theories Batman, what if Satoshi was trying to get the free market to develop free or reduce the cost of energy by giving an incentive to make energy delivery more efficient?
*edit: Even if that is just a side effect, it would be a good one...
