Guys, please learn the way Bitcoin works, this thing is discussed to death. As long as Bitcoin will be a viable currency (which, as things look now, seems to be a REALLY long time) mining will exist. Mining doesn't only mint new coins and puts them in circulation, as most people here seem to think. It also verifies transactions and secures the network. If mining is done with, Bitcoin is done with. They won't exist one without the other. Also, miners don't get money from discovered blocks only. They receive the fees from transactions inside discovered blocks. This will more or less compensates the loss in income from reducing rewards over the years.

So the only way "after Bitcoin" exists is if Bitcoin dies. Which, hopefully, won't happen. And seeing the momentum it gains, this becomes more unlikely with each day passing.