I use my address book a lot to look up mailing addresses. The address book in the People app doesn't always display somebody's complete address, especially if it's a bit longer. This has been bugging me, so I started looking for a replacement address book to use for this purpose. What I ended up with is Phonebook from Voxmobili. There are some comments in the feedback indicating it doesn't work, but it works just fine on my Eris. It actually has a very "touch friendly" interface for using one handed and includes a dialer. It's not as sophisticated as the People app, but once you select a contact, you can press the "details" button & bring up their information, which shows all of their mailing address in one place. I don't think I'll use it on a regular basis, but when I need to view a mailing address, this is where I'll go.

I was looking at the Phonebook app from Asurion but it doesn't support 1.5. Looks like it would be interesting otherwise.