When I bought my 4.4i in 2006, it stretched me to the limits (financially). I decided to go with a bare "naked" 4.4i from the factory, and decided to skip the Nav which would have added another $2-$3K to the cost. I figured I could pimp out the 4.4 bit by bit with after-market add-ons, which is what I've been doing.
For the navigation, I've been using VZ Navigator for the past year or so. It's actually quite good! The screen is obviously smaller than most of the dedicated Navis on the market, but it's very versatile and the newest version has traffic re-routing. It talks to you in 1 of 5 voices that you pick, and has the same 2-D and 3-D routing of all the good navi units out there. It hasn't steered me wrong yet.