Very, but perhaps not like some think. Sure, I want you to look me in the eye when we talk but it's important to not get carried away. In business, I found some people that would look you in the eye so much that it was obvious that they were concentrating on it and I would think..."Rookie". There were others who didn't at all and I thought, "lack of confidence". You don't want to stare down your first date...she may be intimidated or just think you're a weirdo.
Point is, eye contact is important but needs to be balanced and based on the scenario you're in and who you're dealing with. I see it as an art but usually if you just act natural, the appropriate eye contact will follow.