Is it tacky just to serve Hors'd oeuvres at my reception?

This is just fine and not tacky at all. Make sure you put in the invitation that "An Hors'd Oeuvres Reception Will Follow the Ceremony" so guests understand up front what is being served. You may want to get married at 3:00 or something, when people are not hungry for lunch or dinner. If you serve wine with the food, this will make it even better. But anyway, people who come to a wedding for any other reason than to celebrate with the bride and groom are the tacky ones.