you don't mention how much you're willing to spend, so that makes hard to suggest what might work for you. You mention structure you've sunk, so DI might be a good one get, or just a good mid level 2d sonar. A hand held gps unit will mark structure with a simple DF/FF, or you can get a 2d/DI combo with the hand held gps, or a gps/DI/2d. The possiblities are almost unlimited, it all depends on what you what, $$, and how you fish, whether trolling, hovering over brush piles, spider rigging, whatever method you prefer.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.