If I were still maintaining my rather-too-morbid list of Nonagenarian New Testament Scholars, Joseph Fitzmyer would have been on it. He died on December 24, at the age of 96.
1981 and 1985 when Fitzmyer was in his 60's, I still regard it as one of the top three or four English-language commentaries on Luke.
I read Fitzmyer's Spiritual Exercises Based on Paul's Epistle to the Romans (Grand Rapids: Eerdmans, 1995), in 2006 as I was preparing to teach Romans for the first time, and found it very helpful. Fitzmyer's major Romans commentary (AB, 1993) created a stir when it came out because the Roman Catholic scholar's exposition of justification by faith sounded so Protestant.
Acts (1998), a disappointment to the seventy-eight-year-old Fitzmyer, who had wanted to publish a major two-volume treatment to match his commentary on Luke, but was forced by the publisher to limit the commentary to a single volume.
I confess that I find Fitzmyer's Acts commentary a bit thin, and I typically turn to other commentaries on Romans first, so I was surprised and delighted when I recently acquired Fitzmyer's 2008 Anchor Yale Bible commentary on First Corinthians and discovered that it is a gem. My initial impression is that it is one of the best recent treatments of the letter--thorough, up-to-date and incisive. I expect to consult it regularly as I prepare to teach 1 Corinthians this semester. As far as I can tell, First Corinthians was Fitzmyer's last major work. Not bad for an 88-year-old.
Perhaps as remarkable as Fitzmyer's longevity and scholarly productivity during the final four decades of his life is the fact that his doctorate was not in New Testament at all. Fitzmyer earned his Ph.D. in Semitics from Brown University in 1956, and made major contributions to scholarship in Aramaic, early Judaism, and the Dead Sea Scrolls.
For more on Fitzmyer's life and work, see the collection of remembrances at America Magazine: "Remembering Joseph Fitzmyer, S.J." as well as this fine tribute by Lawrence Schiffman, delivered in 2001; the wikipedia entry on Fitzmyer is also very good.