Maybe everybody already knows this but if you want to get addresses from your Mac Address book into your Garmin, there is a way. Read below if interested:

Here is the model I bought:

Amazon.com: Garmin nüvi 285W/285WT 4.3-Inch Widescreen Bluetooth Portable GPS Navigator with Traffic: Electronics

The unit hooks up to my Mac via a provided USB cable so I just assumed I'd be able to get my address book contacts into the unit but it was not obvious or simple. Fortunately, google came through and found me this:

POI Organizer Web Site

This converted my addresses into a POI (Points of Interest) file and then Garmin has a piece of software on their site called POI Loader which loaded the file onto my GPS unit. Worked flawlessly and saved me a lot of work so I thought I'd mention it here in case it helps somebody else.

NOTE: The addresses end up in a non-intutive place on the GPS. Go to:

Main Menu > Where To? > Extras > Custom POIs.

They should all be there and mine were sorted by distance (shortest to longest). From there, you can save any of the addresses to your favorites as well.

Cheers!