Jeff Vogel’s new series, Avadon: the Black Fortress is available now for Macs. The Win version will follow in a couple months. Vogel is the only major developer I know of who releases on the Mac first. I thought some of the Mac fans here might enjoy strutting their experiences first. 
Here’s the link to the game -
http://www.spiderwebsoftware.com/avadon/index.html
And the forum -
http://www.spiderwebforums.com/forum/ubbthreads.php?ubb=postlist&Board=38&page=1
And here’s the blurb:
I haven’t played this yet since I don’t have a Mac but I’m super excited. To my mind, Vogel is the best RPG developer working today. His Geneforge and Avernum series are simply amazing in terms of depths of world and the choices he asks of his players. Geneforge especially. The choices in that game are sometimes so deep that I have to take a day or two to think about what I want to do.
One of the bullet points in Avedon’s feature list is:
This is no joke. The choices in his game aren’t just cosmetic stuff where you do the same quests but maybe in a snotty tone of voice. And it’s not just that there’s a “good” side and a “bad” side. His villains are real people with rational goals and points of view. The writing in these games is second to none.
Avedon is an all-new engine with fresh new graphics. Some people have been turned off by the look of the previous games. The interface design is still recognizably a Jeff Vogel game but much, much easier on the eyes. Here’s the screenshot page if you want to take a look -
http://www.spiderwebsoftware.com/avadon/shots.html
All of Vogel’s games feature enormous demos, at least a quarter of the whole game. The demos are feature complete and are a lot of fun even if you don’t push on and finish the game. It’s very much worth your time to check it out.