Looking at the restaurants alone, then probably Fire and Ice. It's sort of like a Mongolian BBQ, something that I don't have near me, but do like the style. ESPN zone is basically a meg sport bar. I can get the same food near me just not with as many or as big of tv screens.
However, if a game I want to see was playing it would surely be ESPN Zone. Also Fire and Ice is nice to try but Garden Walk is a bit far so if I wasn't staying near it or had a short visit I'd be inclined to skip it too.
If you just want to try them for a new experience, then Fire and Ice would be my suggestion.. Often they have a deal through restaurants.com, though not currently.
http://www.restaurant.com/rdc/fire-...-american-restaurant-rid=365093?&mcn=00068461