In spite of the recent 5-star reviews (from people who have not posted reviews before) I agree with songliner.
NovaMind is a good application, but the upgrade prices are out of touch with alternative solutions. I still have version 3, but don't use it anymore.
The last mind maps I did were created with XMind Pro. Not very Mac-like, but it got the job done and currently costs less than a NovaMind upgrade.
Another great option that I will keep in mind is Mindjet's MindManager. Since the time I purchased NovaMind I liked MindManager's look and feel. NovaMind looks a bit cartoonish and MindManager has a more professional look. Still, I decided to go with NovaMind, mainly due to its integration with Merlin (and the idea of supporting a good Mac developer), but I was happy to find that MindManager integrates with FastTrack Schedule, which I also use from time to time.
This one is definitely not for me. I was shocked at the jump from 3.2 to 4.0, and then shocked further by the upgrade fees.