With most Garmins you can add to the POIs yourself via a file you can create.
Updated maps & stuff are available on Garmins site, and there should be a USB cable that came with it to update the unit if theres no memory card. My friend bought all of North America for his C320 for like $15.
I'll be getting the Garmin C530 soon.
The C530 & C320 are the best bang for the buck.
Current
2008 M5 6 Spd
2000 Z3 2.8 5 Spd MSport
2012 X5 35d Sport
1995 540i 6 Spd
1992 535i 5 Spd
Former
1995 530iA
1986 635CSI 5 Spd
2011 X3 2.8 MSport