Gemini Exchange is an exchange based in New York, US. It only trades three currencies: US dollars, Bitcoin and Ethereum. It has low fees of 1%. It offers high security and compliance, top of the line cold storage system that stores information offline, access controls, and multi-factor authentication.
Gemini recently added support for more cryptocurrencies such as Zcash. This was a huge addition as Zcash is a privacy-focused currency and very few exchanges allow direct purchases of privacy cryptocurrency.