"A sniper's bullet can take away an earthly life, but it cannot kill love," the Rev. Charles Updike told hundreds of mourners at First Baptist Church.
Buchanan served on the regional board of the Boys and Girls Club of Greater Washington and volunteered with a Crime Solvers hot line.
He was also an amateur poet with plans to propose to his girlfriend, Stephanie Lykins. In a Valentine's Day poem to her, he wrote, "Sometimes we meet someone whose eyes smile into our soul ... and that someone is you!"
At his funeral, Lykins described Buchanan's generosity, then said simply, "Sonny, I love you and I miss you."
James Buchanan Sr., a retired Montgomery County police officer, said he raised his son with stories of living through the Depression and the idea that everyone should have the basics in life.
"I told him, 'If you think you have it bad, you look around and you can always find someone else who has it worse than you,'" his father said yesterday. "He literally took that to heart."
Buchanan had given up his landscaping business to help his father build a house on a 32-acre farm in Virginia, but he returned to Maryland to honor a decade-old contract with Dorothy Fitzgerald, owner of the Fitzgerald Auto Mall in White Flint where he was slain Oct. 3.
"He always cut Dottie's grass," said his friend George Jones.
After the service, friends and relatives gathered to drink coffee, eat cookies and swap stories of Buchanan.
Gregory Wims, vice president of the Boys and Girls Club of Greater Washington, said he remembered how for the past several years Buchanan chopped Christmas trees to sell at a mall to raise money for the club.
"He loved his neighbor as he loved himself," he said.