researching airfares

The quest to find the best airfares never ends, but new web tools keep popping up:
- FareCompare shows fares over an extended time period, so it's easy to find the cheapest time to travel on a particular route.
- FareCast tries to predict if a particular fare will go up or down over the next 30 days, and makes a recommendation (e.g. "Buy Now" vs "Wait").
- Kayak and SideStep have been my most reliable sources for finding cheap flights over the past year or two, and now they've merged. I hope nothing much changes.
- I also recently found a good deal on a flight to Argentina using ATIflights.