Surprisingly for a publication which originated in print, WashingtonPost.com generally does a very good job of writing suitable headlines for the web.
For its home page and various section pages, the post tends to write brief, attention-grabbing heads. Its story pages usually carry longer headlines which include the terms a reader would plug into a search engine when he or she looks for the story.
A case in point is the April 14 Metro page headline "Tea Time" which leads the reader to a story about tax day protests. The story page carries a much longer headline which reads "Tea party activists protest high taxes, excessive government spending in D.C." - thus hitting all the relevant terms anyone could possibly want to plug into a search engine.
Again surprisingly, web-only publication Slate.com is extremely prone to cutesy headlines familiar from print. Case in point: "Nebraska feels your fetus' pain," the headline for a story about a new abortion-related state law in Nebraska. Apart from "Nebraska," that headline does not contain any of the relevant search terms. Thus, while it will definitely grab the attention of a reader already on the site, it is unlikely to show up at the top of a potential reader's search results.