of course we will, the less the better for the future of Bitcoin,isn't it?

Impossible question. It depends on all sorts of things since the cost isn't determined entirely by mining now, but also the cost of data transmission in the future and how blocks and the blockchain are compressed. How do these millions of transactions affect data drive and RAM MTBF and what's the cost to replace damaged components? What's the price of CPU cycles in the future? Each transaction today is a burden on our kids, our kids' kids, and our kids' kids' kids' kids, and those burdens would have to be accounted for in determining what's fair, which is impossible (or at least very time-consuming to estimate). -And unless the protocol changes radically, there's no way to pay them this theoretical fair price, anyway, since it all goes to miners.

... maybe $.08-25.

Well whatever it is now is fine..pretty happy with it! Dont mind it getting any cheaper though!

This is really the only correct answer. If you pay less then what the market will "allow" then you are essentially cheating the service provider (the miners) (you are actually probably taking advantage of the fact that they are in need of money) and if you pay more then you are paying an inflated price.

I chose 50 cents - this is of course under the idea that btc is worth 2K or more 

Satoshi said that no tx needs a fee unless the amount you are sending out is equal to or above 200x the largest transaction you have received.

The total transaction fees has been on a declining trend.

https://blockchain.info/charts/transaction-fees

I guess once the block reward halves, transaction fees will become more important.

3600*385=$138.6k

Herp a derp. My bad. Really? It's that much?

Generally speaking the TX fees have gone to the miners since the block reward was halved from 50 BTC to 25 BTC. The only real exception to this rule are the PPS pool operators however the miners are getting a huge advantage of not having to deal with pool variance (the attractiveness of running a miner on a PPS - pay per share - pool/payout system will decrease over time as block subsidies make up a less percentage of total block rewards and TX fees make up larger parts of block reward)