Ars Technica (a must-visit site if you aren’t familiar) has posted a list of Apple’s “Most Downloaded Games.”  I like that it is divided into free and paid downloads.  Some of my favorite games aren’t on the list, but it’s still worth checking out to see what everyone is playing: http://arstechnica.com/journals/thumbs.ars/2008/12/03/apple-reveals-most-downloaded-iphone-games-of-2008

And check out ARS if you haven’t: http://arstechnica.com/index.ars