To my knowlege Nobeltec (owned by Jeppesen) is the most popular PC program which will interface with radar. The 2 KW scanner is about $1800, the program is from $400 to $900, plus a rugged PC (on a C Dory I would not want the hard drive to crash when I went over a wave in critical conditions).
I have seen this in action, and it appears to be a good unit. (not sure how much is being pushed after the Jeppesen acquisition. The units I have seen is on larger boats.
Considering the costs, I prefer to go with a Furuno Radar, with a separate chart plotter (or two). I don't want to get water on my laptop--the dedicated radars and chart plotters are at the very least splash proof. Plus the dedicated units are much easier to use. Try using a keyboard or mouse when underway in heavy weather (I have, but in a 42 foot trawler I owned--and I found it far more difficult than a dedicated chart plotter and radar) Using the laptop/radar in a 22 foot C Dory would be more difficult than on a more stable platform.
Plus I like having the information is right in front of my eyes, so I can keep my eyes on the water, and just glance up or down to see the chart plotter or Radar.