Languagehat—Wide-ranging coverage of language- and literature-related topics, with an eye for unusual language and languages, and a solid cast of regular commenters. Language or linguistic dilettantes and amateurs will satisfy their curiosity and passion here.
Language Log—One of the smartest group blogs on any topic anywhere on the Anglophone Internet, featuring respected linguists and grammarians commenting on the mundane, arcane, and profane. A key to the blog's success is that the various posters disagree as often as they agree—meaning more than one school of thought is represented, rather than whatever is faddish or fashionable. Alas, attempts at allowing visitors to comment proved unviable.
WordOrigins.org—Dave Wilton's site not only features key refutations of common etymological myths (see the "Big List" on the main page), but a chummy group of expert regular visitors in its discussion forums, where the level of discourse is high. And woe to the lazy student looking for someone else to do their research! Dave also offers a free, informative email newsletter.
World Wide Words—You could spend a week on Michael Quinion's site and still not see everything. He's prolific and erudite, mainly from a British English perspective. His weekly newsletter is highly recommended.
Separated by a Common Language is a blog by Lynne Murphy, an American linguist who lives and works in the United Kingdom. She writes interestingly and comprehensibly about the differences between Englishes, covering everyday topics far beyond go to hospital or fanny.
Verbatim, the Language Quarterly. A neat and nifty newsletter with fun, funny, and quirky articles from a variety of authors. You can subscribe to the print edition or see a hearty amount of past content online for free.
Visual Thesaurus is an online, interactive thesaurus that's fun to search when you're stuck for a word. The site also includes articles about and interviews with newsmakers in the field of language. The Visual Thesaurus is published by Thinkmap, Inc., which is an underwriter of "A Way with Words."
Vocabula Review, the home of English-language prescriptivism. Includes contemplative and personal essays on the nature of writing, language, and literature. Subscriptions are cheap.
