I am looking to upgrade and was wondering if anyone had any recommendations for a GPS/Depthfinder Combo. I fish out of an 18 ft aluminum express boat and use it for most anything. I mainly target catfish and spend an equal amount of time on lakes and rivers. If anyone has any suggestions please let me know. I have heard good things about the humminbird 595c and i guess am leaning towards that one. My budget will max out around $500. If anyone has any suggestions I would appreciate it.