I have the Raytheon RL70CRC (Radar/Color Chartploter). I am very happy with it.
With this setup You would need GPS antenna (your choice but most people get the WAAS capable) The Radar Chartplotter, a radome (your choise but most coastal cruiser get the 2kw radome) and of course a mount for everything If you order these 3 things you have a pretty complete system (it comes with most cabling except 12Vdc wire). But what I like is you can add to it. You can easily hook up all your raytheon instruments to it via the raytheon "Seatalk" (3 wire interface). I have my wind, speed, depth autopilot attached. This way I can steer the boat to a way-point or monitor any other instrument from the radar/chartplotter.
This setup will do split screen radar/chartplotter, but it will also do Radar and overlay it on the chartplotter. But beware it will only be close overlay they really want you to install a pricey gyroscopic compass that keeps the chartplotter/gps locked in a closer sync.
Pricing varies Best thing to do is go to Westmarine & defender websites. On sale I think $200 for GPS antenna, $850 for 2kw Radome and about $2200 for SL70CRC (you probably don''t need to get the RL70CRC which only allows the capability for a remote radar/chartplotter station....costs $700 more and most people don''t use it). Mounting vary''s from low end of a few hundred dollars to about a $1000 for a nice self leveling mount.
yes this is expoensive and you might find a cheaper alternative (Monochrome and not color), but I once you see and use a Color monitor, you''ll never want to use a monochrome, its much, much easier to quickly and easily see the charts and radar....its worthe the extra money