Keep your expectations low -- most options here are either chains or hotel restaurants. Not that this means you can't get a good meal, but it's unlikely you'll find a cute little hideaway right in the heart of falls-ville, and even the less expensive chains tend to cost more than usual.
Twenty minutes away in Niagara-on-the-Lake, is some of the best food (and wines, of course) in the Canadian Niagara region. Here you'll find excellent upscale dining at the elegant Georgian-style Charles Inn, 209 Queen St. (tel. 905/468-4588) as well as local favorite Stone Road Grille, 238 Mary St. (tel. 905/468-3474), a casual bistro known for their artisanal cheeses and housemade charcuterie. On the American side, Carmelo's, 425 Center St., Lewiston (tel. 716/754-2311), turns out exquisitely prepared seasonal Italian fare, and is well worth the 15-minute trek from the falls.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.