This plane is huge. It carries up to 550 passengers (in it's 777-300 incarnation, all flying coach). Its maximum takeoff weight is 660,000 pounds, heavier than a fully equipped B-52.

It seems all the more impressive on the runway, because it deceptively has the same appearance and proportions as its smaller cousin, the 737: 2 engines mounted on the wings, rear fins mounted on the fusellage, etc. Only when you see an actual 737 scoot in front of it do you realize how collossal the thing is. The tail fin has about the same square footage as my old studio apartment.

The 777 is also noteworthy for being the first twin-engined turbofan airliner to be certified by the U.S. FAA and DOT for extended transoceanic flight (as in, beyond the short North Atlantic route). This is due to its ability to continue flying for extremely long distances with one engine off - a high ETOPS rating.

Potential advantages of the twin configuration (as opposed to the 747's 2x2, or the DC-10's 1x1x1 include better fuel efficiency, lower noise, a less complex aircraft which means fewer failures, less weight, etc., and more easily synchronized thrust.

Here's a quick technical summary gleaned from Boeing's website:

The 777 is a medium to long-range passenger airliner designed and manufactured by Boeing. There are five models in service - the 777-200, 777-200ER (extended range), longer-range 777-200ER, 777-300, and longer-range 777-300. The standard 777-300 seats from 386 to 550 passengers (depending on the seating configuration installed by the operating airline), and has a maximum range of 5,960 nautical miles (11,030km). It is 242' long, 60' high, and has wingspan of 200'. The 777 is powered by two Pratt & Whitney engines, and has a maximum takeoff weight of 660,000lbs.

The 777 was the first airliner to be designed completely using software tools instead of mockup modeling. The aircraft is 9% carbon-fiber composite by weight (compared to about 3% for other Boeing jets,) and boasts a "fly-by-wire" digital control system. Its engines give it a 40% power advantage over its predecessor (the 767), without generating any additional noise. The first 777-200 flew in 1994; the first production aircraft entered service with United Airlines in 1995.