Your in the right place for software. I purchased a Map 76CSX and a software package earlier this year of ebay. There is a grey area with the software in America that people can sell chunks of the software for a state or given area. I got Southern and Eastern Australia Bluechart, Citi Navigator 2009 and 250,000 km2 Contours for Australia all bundled together on one card for $170 all I had to do was put the card in and go. The guy I got it from in Australia was really helpfull with getting me up and going and I still ask him questions now which he happily answers. In Aus we have some free land based map sets called Shonky Maps and Tracks for Australia. I have recorded my sailing track on Tracks for Australia, you may have something similar in US. PM me if you want the e-mail for the guy that organised my mapsets
regards