Am I strange in actually using an address book for this purpose? You know, one of those things with dead trees in it....
If it's the only thing you carry, then it's not strange at all.
But if you're also carrying a portable electronic device - cell phone, pager, PDA, laptop, etc. - then why carry more than one device? The advantages of convergence can lighten your load. The penalty is typically having to recharge the battery and any service costs but if you already have an electronic device you're already paying that penalty.
My wife used to have a Palm Pilot for contact management (and some games) in addition to a basic cell phone. Then she went with a cell that allowed texting. Then she converged and got a Palm Centro. Besides a single device to carry - she noticed her purse was lighter - the convergence means there's only one contact list to maintain and it's integrated so that she can call or text from within the device itself. And click on an address to launch it in Google Maps. And if I ever talk her into moving off a free Yahoo email account she'd be able to email as well (she isn't willing to pay for POP access).
Other devices like my Pre go even further like launching the GPS with a clicked address and letting you manage conversations across the spectrum of options. Start with an SMS text but continue with Gchat and then write on someone's FaceBook wall before ending the thread with an email that might be followed up by an actual phone call.