The scene with President Bartlet gifting Charlie his old copy of the constitution was the last shot filmed for the series.
President Josiah "Jed" Bartlet does a final walk through the West Wing thanking all his staff. At one point he stops and talks with Nancy and, asking about her mother, says, "I hope to see her real soon." Nancy is played by Renée Estevez, Martin Sheen's daughter; Renée Estevez's mother is Martin Sheen's wife, Janet, to whom Sheen has been married since 1961.
As the Bartlets prepare to return to "normal" life, Abby asks President Bartlet "When's the last time you drove a car?" to which he replies "It's just like riding a bike, except with more horsepower, right?" The very first episode of "The West Wing" opened with the staff having to react to news of President Bartlet falling off a bicycle.
One of the names announced while the President-elect and Mrs. Santos are waiting to go out is William Clinton.
Both the season premiere and series finale have the current President asking "What's next?" at or near the end of the episode. President Bartlet to Mrs. Landingham in the premiere and President Santos to Josh Lyman in the finale. The premiere ended with the question, but the finale had one more scene; President and Mrs. Bartlet on the plane.