Where are your clients?  Google just announced My Maps, a dead-simple way to create a (public or private) personal map.  You can embed photos, tags, links, etc. to each map.

Here's a tip:  Add your client's addresses to a (private) map.  Every time you are running errands or visiting clients, you can check and see if you will be near any of your other clients.  Drop in and say hi.  They will appreciate that you are thinking of them.

Or use it for family and friends!