Graham, definitely.
Graham is soft but strong, and very intelligent.
I see from some of the other posts (didn't read them all) that some consider the GRAM pronunciation predominant in the U.S. I don't know - I live in the U.S. and remember being corrected as a child when I said GRAM crackers.
My ex-father-in-law went by
Graham, pronounced GRAY-UM, which was his middle name.
Graham also is my ex's middle name and our firstborn son's middle name. By the way, these are all U.S. people, and it's GRAY-UM all the way.
I like
Bruce in theory, because of its history, but it has a harsh sound to my ears.
Anyway,
Graham Boyd sounds a bit better than
Bruce Boyd. I'm normally a fan of alliteration, but
Bruce Boyd doesn't do much for me.