One of my favorite affiliate programs is Joe Bucks aka Market Health, a beauty/health product affiliate program. They offer many great products to market, glossy banners/promotional materials for blogs, professional mini-sites; free hosting of product sites for members and even pre-written articles and reviews to post along with your affiliate links. They pay via Paypal. This affiliate company has proven successful especially in my beauty blog niche. What's your favorite affiliate program or network?