Goose, there's no real need for the 50 /200khz unit unless your fishing off-shore waters. Insight mapping is great for those who fish outside of their "regions" (referring to Navionics cards) as you have a map with good detail for most all of the major lakes in the country. On some waters the Navionics cards will show more detail and the reverse can also be true for the Insight maps.
The HDS10 is a top of the line unit and will allow you (w/structure scan) to split your screens (4-way) and easily compare your side/down images to what your seeing in 2D sonar.
The base map units usually sell for about $170 less than the Insight models so if you rarely fish waters that are outside of your region, the Navionics cards may be a better choice. There is also the new Lake Insight HD card designed to replace the original Insight preloaded mapping. I've had customers say they prefer this card over the Navionics and the Insight pre-loaded mapping. Here are some of the specs.
Lake Insight HD U.S. mapcard
For HDS anglers on-the-water and on-the-ice in mid-north U.S. states, Lowrance Insight shaded relief merges with LakeMaster high-definition data to bring a whole new dimension to lake fishing success.
One card with complete, high-detail coverage of continental U.S. inland waters including the Great Lakes, plus coastal coverage.
Immediately-recognizable dimensional and detailed underwater structure viewing
Greatly-detailed shoreline and depth contours for over 2,700 total lakes with LakeMaster high-res surveys on over 440 lakes
High-definition 8m/pixel resolution viewing
User-selectable depth contour lines on/off
Four Times the Detail of Built-In HDS Insight Maps
Eight More Zoom Levels of Shaded Relief Data
Find Fish Faster With Exclusive Fishing Hot Spots
Loads of Free Space to Save Sonar & Navigation Data
Expansive Coverage of Lakes Across the Continental U.S.
Exclusive Fishing Hot Spots detail for over 500 popular lakes featuring marked fishing areas, helpful fishery and facilities information, and more.
High-detail contour lines with 8 m/pixel resolution shaded (dimensional) relief viewing
Over 5,000 lakes with enhanced shoreline detail and depth contours
More than 100,000 names bodies of water