Because I didn't care about the phone automatically going into navigation mode, I went another route.
I used something similar with my Garmin and loved it. This version for the Droid works great and I don't have to worry about the suction cup thing.
You can also easily use it with the Droid in the regular or landscape mode.
Arkon Weighted "Friction Style" Dash Mount & Holder - T-Mobile G1 Car Mounts - Androidians Store