Wakina,
Nice post, and good information! I agree with Wakina about the HDS really only being worth the extra money if you are going to integrate it with other system.
I bought my HDS Gen 2 with no intentions of networking it. Last year however I bought the Lowrance "Point 1" external GPS that updates 10 times / second. Then I plugged my marine radio into the HDS as well. Now my radio displays my GPS position, and... and... If I want to I can "share" my location through my radio and any of my friends can "see" me on their Lowrance HDS units, and I can see them if they have one.
I realize that you are buying it for a fish finder, but if you can see your friends and you can get reports from them, then it is better than seeing what is in the water. For example: I can tell a buddy, "Hey, from where I am right now go NW for 1 mile trolling 2 MPH. We just picked up 6." He doesn't have to ask where I am, and he already has my exact GPS coordinates.
This was not something that I thought about when I bought it, but now it is something that I wouldn't go without.
Wakina is also correct in that any autopilot or radar system is quite easy to set up with the HDS systems and almost "plug & play."
However, he is also correct about needing to be an attorney... lol
My brother who owns the boat with me is an attorney in Pittsburgh and he spends a couple hours each year reading and learning about some new feature for us to start using... It's pretty comical that Wakina mentioned being an attorney in Philly!
-Matt