From all early reports, it seems like the Mars Curiosity landing went off perfectly. So many things could have gone wrong, and almost any one of them could have resulted in disaster.
NPR’s Joe Palca had a good report that captured the sequence of events during the landing, the rising tension as each critical stage approached, relief as it was completed successfully, and the final jubilation when Curiosity touched down.
You can read more about the mission and see the first photos beamed back at the NASA website.
Congratulations, NASA! Curiosity is a tribute to science and engineering at its best.