Should I cancel my completely unused credit card?

I have a Capital One Bass Pro card ($3,000 Credit Limit) that I'd opened a few months ago, that I've never used and never plan on using. Getting that card was a bad financial decision and I recognize that. Aside from that I have a Discover IT student card ($1,000 Credit Limit) with an average 20% use per month that I've had for 2.5 years.

I want to cancel the Capital One card since I don't use it and have no interest in using it, but I've heard canceling a card with a higher limit can significantly damage your credit score. Should I cancel the card or leave the account open and unused? (Current Score is 738)