Tor.com may be the website of one of science fiction's biggest publishers, but their blog has tried to promote good books regardless of the publisher. And now they're extending this "agnostic" approach to their new online store, with fascinating results.
The Tor store includes a ton of science fiction classics, as well as newly published titles from several different publishers. But honestly, the main feature of the site that's really unique is that it provides a central repository for all the titles that the site's columnists have recommended (and a place to buy those titles, which doesn't hurt either.)
The most engaging content at Tor.com over the past year has frequently been Jo Walton's eclectic recommendations, and the essays she's written about each title — and now there's a handy list. Other lists of recommended titles include Ellen Datlow's "most influential books in SF" (which wouldn't be a bad primer for someone wanting to discover the genre for the first time) and Daniel H. Wilson's list of books about "robots, robots, robots!" It's a pretty great resource. Check it out!