Here is a review of and links to some different open source genealogy programs - open source means that the source code is open and anyone can tinker with them all they like, they're also totally free for download and use, even if you're not up to tinkering with a program!
And there's just some stuff that looks good on this site:
http://www.cameraontheroad.com/family/family-history-and-genealogy-...
GenJ looks interesting, here's a screenshot and the website says: "GenealogyJ is a viewer and editor for genealogic data, suitable for hobbyist, family historian and genealogy researcher. GenJ supports the Gedcom standard, is written in Java and offers many views like family tree, table, timeline, geography and more."

Another one on there I like the look of is GRAMPS: "... a genealogy program based on GTK for Linux, Windows and FreeBSD that allows you to easily build and keep track of your family tree." It appears to have an easy to fill out form which allows you to include a lot of information about an individual person. I downloaded this for myself, as it's good on Linux (and Windows), but I haven't tried it yet.

There's also GenerationX which is written specifically for MAC OSX, but there was no screenshot available for this program and I don't have an apple so I couldn't check that out.