MetroTwin.com pairs two great travel hubs, New York and London. Whether you're traveling to one of them for the first or fourth time, you'll find new things to do and restaurants to try offered by local experts who know their turf. The site is run by British Airways, but I didn't get a sense that this affected the information.
What's hot: The "Twinning Places" feature takes one location or attraction from one city and pairs it with its across-the-pond counterpart. For instance, the Tate Modern Shop in London is linked with the MoMA Store in New York. I love the "Lists" in the top navigation bar, which include such topics as "Best Hotel Bars" and "Mondays at the Museum." But the most user-friendly areas are the categories (found in the top navigation bar), which take you to the types of local spots you want to find on the road: bars and clubs, shopping family places, hotels, restaurants and more. Click on the title to get a stand-alone page with user reviews, a Google map and a chance to twin it with something in the other city. You can give a listing a thumbs up if you like it, flag it if you've been there or save it to your profile for a future trip.