This is what I use. Acutally i interchange it between my two cars.
It is a Hard Drive based system which can be updated via USB port over any CPU after ordering updated maps (DVD) from the Manufacturer. I like it because it loads fast and I can take it out of the car to plot trips in my home or hotel room instead of sitting in the garage inside the car. It has 6 million POI programmed in it for all of North America. Unfortunately what you see here is an old model which i bought 2 years ago ($1200CND), i think there are newer ones out already. Oh yes, it's touch screen and it voices out street names, for example the unit's female voice says" in 250 meters, turn left on Victoria Street, then keep right". I just stated Meters but i can change the settings from Metric to Statute or from meters to Miles.
check out
http://www.garmin.com/mobile/products.html#automotive if you're interested.

here it is sitting comfortably on my computer table ready to plot trips or ready to be updated via computer USB Cable. At the bottom is a BeanBag mount, it's heavy and it's rubber padded; i place it on the dash to the left just behind the steering wheel and it never flinches or moves even on bumpy roads.
No removable memory with this one, i think that's only for the older and cheaper less than $800CND units. this one is ready to use out of the box with maps already programmed in its hard drive from the factory. This one came with City Navigator North America V7 which has been out for about 2 years now, but I read that CNNA V8 is coming out soon and should be good for another 2 or so years.
good luck,
gj