You may want to consider using some the next time you install the bulbs. I'm not sure of the exact name, but its a kind of grease you add to the socket. I know it seems counterintuitive, placing a liquid substance into an electrical socket, but its supposed to help prolong the life of the bulbs. Just ask someone at Advance or wherever if your not sure what I'm talking about. Maybe someone else here can come up with the name, I'm drawing a blank at the moment. But your certainly not alone with this problem. Almost every 00+ Bonneville I see (except for mine) has at least one out. And it doesn't help that the owner'* manual doesn't even admit to their existence.
-Austin [aka: SapphireTorrent]
2000 SSEi "Black Bertha."