May I suggest since your recipient will be living in The Marina District (i believe that is what you are referring to), then they are certainly familiar with Chestnut Street which is THE commercial St in The Marina... Perhaps you can contact Kara's Cupcakes http://www.karascupcakes.com/locations/ and have a wonderful cupcake gift waiting for them to pick up? Not sure if Kara's delivers, but check them out...Who doesn't like cupcakes! :)
Best wishes to your friends in this vibrant SF neighborhood!
My business partner/brother and I usually leave a nice bottle of wine at the property address (if your clients like good wine of course) and send a nice edible arrangement to their workplace! We've gotten some good feedback from both of these ideas in the past.
http://www.ediblearrangements.com - they have a lot of choices at various price points so you can pick something that fits their likes and your budget.
Hope this helps!!
Realtor, Vanguard Properties