zildj

I haven't tried any navigation in US, just in Europe and Australia, but all should also have pretty good US coverage. There are many good GPS navigations on the market :

Sygic Aura - try before buy, needs GPU, no problem on DHD
https://market.android.com/details?id=com.sygic.aura&feature=search_result

all others doesn't have trial period :
https://market.android.com/search?q=gps+navigation+USA&so=1&c=apps

I've also tries NDrive 9 (in Europe) and it was good, but new version is not rated well :
https://market.android.com/details?id=com.ndrive.androidusa&feature=search_result

Sometimes I also use Navdroyd, but carefully, this is just very basic and not user friendly (but works at least), maps are compiled from OSM, so they are not so good as commercial ones :
https://market.android.com/details?id=com.osa.android.navdroyd&feature=search_result

It's hard to get iGo legally, it can be installed just by telco or bought just in Hungary. I've tried some pirate versions by myself (but it's not legal and allowed on this forum) and it sucks, other navigations are better (much more stable and run at all). It's not allowed to share illegal links, but it should be easy to fix these :-)

xttp://www.kat.ph/igo-north-america-usa-for-android-t4101837.html
xttp://www.mobilephonetalk.com/showthread.php?79675-iGO-My-Way-for-Android-All-Maps-POI-s-Buildings