Lowrance HDS Series – If you have the budget, the Lowrance HDS is a no-brainer. With powerful maps, very good SONAR, and the ability to add on DownScan and Side Imaging together with the LSS-2 StructureScan module, your fishing boat will become an unstoppable fish catching machine. You can also hook up any NMEA 2000 compatible electronics to see them on the HDS display. But my favorite feature, by far, is the fact that you can overlay Side Imaging data on a map and see both SONAR and mapping at once. The HDS series comes in sizes ranging from 5 inches to 12 inches, varying in price, too, so there is something for every budget.