Food.com's recipe search is worth getting excited about. It comes from Food Network founder Scripps Networks, but can pull recipes from Epicurious, Food & Wine, Cooking Light, Gourmet, Chow.com—basically, any US food site you've heard of.
Not only does it pull basic recipe links and descriptions from all those third-party sites, but it grabs the full ingredient lists, pictures, user ratings, and preparation/serving instructions, then categorises them for search refining. So if you're looking for a Vietnamese dish to whip up tonight, but you don't want anything deep-fried, and you'd like the main ingredient to be chicken, Food.com can help you get there.
You can save recipes you find to your "Recipe Box" by grabbing them whole and dragging them into a little AJAX box at the bottom of your page view, and also add recipes to your box from sites not covered by Food.com's rather extensively searchy fingers, or upload your own entirely new text recipe. There's a toolbar to help with collecting and searching recipes (as if you didn't have enough already—where's our bookmarklet?), and the front page provides a history of your searches for quickly getting back to what you just found.
It's hard to believe it took so long for someone to offer a recipe search with this kind of breadth and functionality. The service is still in beta, so you'll need to sign up and log in to use it. From a first look, though, it's definitely worth it.