What is your favorite site for plannig a voyage or a trip, for travel?

I like to use the Lonely Planet Internet site. The Destination Guides offer a brief introduction to each country where I like to check on costs for accommodation. I then look up discussions on the Thorn Tree to see what other travelers say about the places I plan to visit. I look up the current Lonely Planet Guide I either buy or borrow from my local library. You see, I like to get the most up to date information and sometimes their books can be a bit out of date. If I am planning to train by train once I reach my destination I have a look at the Seat 61 Internet site. It had details for train journeys in the whole world. It also has links through to book train tickets. It has far more description than a book like Thomas Cook Timetables.