Logic 9 is the major facelift, it is what I'd consider the X version. Very awesome software, 64-bit, Core Audio/Video/Animation, so it'll run in Lion and be good for a few more years. Or go ProTools. How much money do you have to spend?
As a composer/producer, I find it way nicer to work with then ProTools in my own studio. Best project studio app around.
How intense and heavy is your audio work? Are you recording lots of live instrument tracks, using lots of midi tracks, doing lots of multi-takes, piling on lots of audio processors?