Up until a few months ago, I would have sent you straight to a Lowrance unit, specifically, the 525 series. Since they have come out with the HDS series, it appears people (my father and I are included) really dislike the changes. I just set a Garmin 541s in my new boat and love it!
I think Lowrance made a bad engineering choice and the Garmins are now more user friendly and have great detail.
Hope this helps!