Currently working on an application, which will be released on Multiple platforms, targeting OS X and Windows devices first, followed by iOS release. The current focus is on the OS X version, which will be released first.
During the design process, I have opted for Myriad Pro. Which suits the application in various areas very well. i.e. Titles, Labels, Menu Texts etc.
After some research though I have released it is not shipped with Macs or other OS.
I am currently working on OS X Lion and have no access to Avenir, however, I had the chance to try Helvetica and H. Neue, which looks fine but does not fit as well as Myriad Pro.
What fonts should I try to use?
What would be your suggestions as experienced designers on the subject?