Before reserving a seat on a flight I always check the seating arrangement on SeatGuru. By choosing airline and equipment, the site will provide you with a seat chart with color indicators for good and bad seats.

As airlines continue to reduce the pitch (distance between seats) it helps to determine which seats may be better (read: more comfortable) than others. For example, we all know exit rows have more leg room, but on some planes, the exit rows may not recline. JetBlue, for example, offers 3 more inches of leg room on the back half of the plane. And of course, we all want to know how far away we can get from the lavatory and the obligatory line of people which seems to form after takeoff.

Link: SeatGuru

Someone finally put Google Maps and Wiki together to create WikiMapia. Users can add boxes around locations on the map and add their own content.

The site is pretty new so you will probably be one of the first to highlight locations. I have already extensively marked up the Washington, DC area.

Link: WikiMapia