Software On Board is another program that may be of interest.
It comes with 15 C-MAP NT+ regional charts around the world that are in the most detail available. If you sail in one of those regions you will find this quite useful. Otherwise the additional areas will be a bit expensive.
Go to http://www.digiboat.com.au
Here's what they say:
"SOB is freely distributed for a 6 month trial period. Thereafter, SOB will revert to a LITE version (with some advanced features restricted or disabled) unless a User License is purchased. The LITE version will still be suitable for basic navigation, however we obviously recommend you purchase the User License so you can continue to use SOB with all its features and benefits. The User License for standard, private SOB use is USD50.00."