Both have their own roles to play in the future.
I don't think bitcoin will make banks disappear because bitcoin has it own issues and limitations.
Bitcoin and banks both have their limitations and advantages, people are the ones to choose best for themselves.
Well I think it will disappear banks in future because of decentralized economic system i.e. there will be no need of banks for monitoring for international transactions because in decentralized economic system bitcoin users will only be responsible for their actions. Beside all this it will be tax free. And this will make your transactions safe and sound and the sole reason behind such fame.