I have the Garmin 162, its a gray scale machine and I love it!!!!
You can load all your numbers into it and thwen mark spots when you are there.
Whats nice with the color unit is that you can see most in the sun!! Mine sucks in the sun light.
I have been in fog so thick you can't tell weather you in the water or the sky! Always gets me home!!
IMO there is nothing better then a Garmin! I have had handhelds and fixed mount and garmin is easy to use and they work great!
They come with internal Att or external, I have the internal and have no problems with the windshield or the Bimi top, always has a signal.
You can get good deals on some on ebay, here is the spec on the 162 if you are interested:
http://www.garmin.com/products/gpsmap162/#