I think it is more likely than not that the wealthiest members of Bitcointalk are unknown to the community.  However, if I were to take a guess at who had the biggest cypro assets on this website, I would say MemoryDealers.  I think coblee probably has a nice stash as well.

The founders of Binance, Coinbase, & Bitpay could be in the running also (didn't look up all their usernames).  It's difficult to say because the personal decisions of these individuals with their funds likely had a massive effect on what happened to the wealth they created.  It's pretty safe to say all those mentioned are multi-millionaires though, likely in the high 8 or 9 figure range.