Just two links today...
When you're fond of beautiful mechanics and of technology, like I am, you're definitely in aeronautics.
Airliners.net
As a starter, AirLiners.net, a must see ; more than a million of pictures online! Mostly big airliner (hence the name of the site...), from which many of them in rather weird situations, like on the famous St. Marteen airport... And a few jewels like this northern lights picture, shot in the North Canada... I let you search.
PilotList.org
The second link is a site on which I go pretty regularly. Not a single picture here, text only : PilotList.org. Sorry guys, that's in French only!
But if you can read French, this is a pilots mailing list, whatever their skills level, from the beginner to the Captain.
And, especially, we find there articles written by Jacques Darolles, Captain on Airbus A320 (but he usually signs with an hume "Conducteur d'engins" - Vehicle Driver...), author of the book "Le plus beau bureau du monde" (The most beautiful office of the World). He has a really great writing style, for those of you who, just like me, are dreaming whilst watching the aircrafts taking off,a nd love all those processes which are behind a long-haul flights...