I agree. There's no ceiling on how high bitcoin can go. There's trillions of dollars of wealth in fiat currencies already, and bitcoin is the best-known, most sound currency around. Also, you can buy bitcoin in such small amounts, it's very difficult to price people out of buying it. You can't split a dollar in half, but you can split bitcoin.
Unless something comes along that's better -- which could easily happen soon, with all the new ventures in this space -- bitcoin could go to $1 million. Absolutely.