I've been flying computer flight sims since Sub-Logic on Apple II in 1980, through Atari, many others, ATC, and finally all the versions of Microsoft Flight sim right up to FS2004. I lost interest for a few years and put my FS gear away (i.e. control yokes, rudder pedals, quad throttle, hud cap, switch panels, etc). In last year or so decided to get going again assuming I'd be running the latest Microsoft version via VmWare on my mac as I don't suffer PCs anymore - but discovered Microsoft quit the FS business years ago!!! Bit of googling and various FS forum reads later, discovered X-Plane which runs on Mac and PC seems to be 'de rigour' and in favour, so bought a native Mac version and have to say even at this very early stage quite impressed with the flight dynamics of the thing. Great for IFR with excellent weather patterns.
http://www.x-plane.com/desktop/home