Quick version: Centrafuse
I used VOICES loyally for almost a year due to its tight integration with mappoint and its simplistic interface. To tie it all together it supported voice control and prompts and ran quite well for the most part.
A few months ago I decided that I was going to get my hard disk replaced under warranty as it had locked up 2 times in 2 months. Looking around for a replacement front end, due to the lack of voices development, I tested most comparible frontends out there. Conclusion? Centrafuse was the closest replacement.
So if you are looking for an application that ties into GPS in a sweet way, head to the CF forum! Note CF uses destinator, however I believe D3 to be a far superior application (tip use 3d maps) to mappoint in regards to accuracy, usability (ability to follow directions without gps screen up in front) and layout.
Asus Pundit Barebones PC
7" Lilliput LCD
P4 2.8ghz 512mb 120gb
Windows XP Pro, VOICES
Sony Xplode 10in Sub, Rockford 600w amp
Pioneer 6x9's and 4x6's, Kenwood 4ch amp
Black Widow Alarm with Pager