I see there are a few ethereum decentralized exchanges out there. Are they really safe? Is there one currently in existing? Will this save me from getting MTgoxed in the future?
EDIT: Uniswap has proven to be a safe, decentralized exchange and has been operating since November 2018.
Yes, an open-source, decentralized exchange like EtherEx will avoid MTGox shenanigans.
It exists on testnet currently, as it says:
geth --testnet --rpc --rpccorsdomain http://etherex.github.io
It is fully open-source at https://github.com/etherex/etherex
From the source, you can see that there are no backdoors where anyone can get special access to and can run away with your funds. The whole community is welcome to audit the code to check that there are no accidental bugs that make it less safe.