My favorite free sites are:www.epicurious.com
(Bon Apetit and Gourmet magazines)www.foodtv.com
(Emeril Lagasse site)www.allrecipes.com
(less elaborate, but sometimes useful)www.recipezaar.com
I'm sure there's more, but all of the above have several thousand recipes and growing. I tend to stick with sites that I already trust the recipes from the original sources (like the first three mentioned). Plus I also rely heavily on user reviews of the recipes (epicurious, allrecipes and recipezaar).
And, of course, don't rule out the search engines. I just googled my way to a Paczki recipe, mainly looking for the official history.