Sometimes I think it's unsafe to tell a person to their face we're no longer interested.. especially if we've met them online and we're still in the getting to know you stage.

I would end the night with a positive and let him know you'll talk with him soon. Then via phone call, be honest.

Just say something like, "It's been fun getting to know you. I'm not sure I see a future together though. I hope your next lady will be everything you're hoping for. Thanks for the ___."

Cheesey? lol