Mine for transaction fee cause the fee would be really high if everyone starts using Bitcoins....
I can't wait to see where transaction fees will bring the block rewards to. IMO, I think we'll see larger payouts from transactions than the 50 BTC rewards of the old days ..not tomorrow, of course, but in good time. In fact, it wasn't long ago that I saw a 6-8 BTC bonus of transaction fees on a block solved by Slush's pool.
Very unlikely. Tx fees are likely to remain low. Then again the purpose of mining is to secure the network not get rich quick. As the value of BTC rises the nominal amount of BTC paid in fees per tx will decline. The rise in tx fees will partially offset the drop in subsidy but we are unlikely to ever see a 50 BTC block again (baring some insanely expensive one time mistake by a user). When the block subsidy cuts again to 12.5 BTC we probably will never see 25 BTC blocks and etc.