I will have to give his wedding gift some more thought. Whatever it is I know what I would like engraved on it...it's a line from a White Stripes song that I always say to him.
Hey, hey, hey! Just a minute there, girlie. How dare you mention a "special sentiment" and then not let us know what it is. Come on. Inquiring minds wanna know.

Sorry to leave you hanging! The entire line goes "I wanna hold your little hand if I can be so bold, and be your right hand man 'til your hand grows old." I would probably shorten it to "Will you be my right hand man 'til our hands grow old?" or "'Til our hands grow old". I like the idea of a pocket watch...I think he would think it is untraditional enough to be cool. I would pick the shorter line for the watch so it would fit and put our wedding date at the bottom. That way the line could symbolize our hands and the watch's hands. Do you think it's too corny?