Hi! My name is Leonid, I live in Kharkov, Ukraine and work as a software engineer. Here I record notes on programming, system administration and other, completely unrelated, topics. Some posts here are in English and some are in Russian.
Skype (not really a website, but an Internet application)
I am also impressed by TripIt; if I traveled in the US, I would use it, and Kayak or Farecaster for flight booking.
Now my own picks.
Skype is great for PC-to-PC calls, and probably for PC-to-phone calls in the Western world. Unforunately, here in Ukraine Skype has a severe limitation: for reasons that are hard to comprehend, Skype doesn't allow to buy Skype credit with a credit card from Ukraine, essentially making SkypeOut service unavailable for Ukrainian users. Given how expensive international calls from Ukraine are, there seems to be a great market for VoIP, yet Skype chose to ignore it. Luckily there are others to fill in the void. VoipDiscount readily takes payments from Ukraine, has reasonable sound quailty, is actually cheaper than Skype, what else could you wish for? Once you make a 10 euro deposit to your VoipDiscount account, you are given 120 days of free calls to major developed countries, and quite cheap to the rest of the world. Once your 120 days expire, normal rates apply to all destinations, but still this is really cheap, cheaper than Skype.