Is there a website where I can view the wealth distribution of BTC and different altcoins?
I know such data are only estimates (address != holder, exchange wallets, etc.), but would still like to get a feeling of how different coins are distributed among its holders.
I don't think there is one. But there were lists of the richest Bitcoin wallets that have been spreading. There is no big deal to those information though. Those wallets that are known to be the richest are definitely not owned by individual Bitcoin supporters or even early adopters. They are most probably wallets of institutional investors, companies, and exchanges.