The Mac is a good idea, in that it's a more transparent audio production tool than a PC, but the Protools thing is questionable. Any native DAW can do what PT does for 1/4 the cost, unless you're talking about LE, in which case any native DAW can run circles around LE for the same cost. However, if you're buying into the whole PT compatibilty thing, I suppose it could be valid for you. I don't have PT, but I still interface with PT studios by sending a stereo mix in generic wav format, and getting back generic wav files, all starting at zero, to import into DP. Or I send out a project to be mixed in generic wav format. Many well known mix engineers prefer a project with no plugins or automation, so what's the point of sending them a PT file when a generic wav format project would suit their preferences? But, if you're not a producer or player, and your only draw is running a PT rig, then you may have to bite the bullet.
Good luck, my friend. (Not with the Mac. The Mac requires no luck - but with the PT thing.)
"You're either with a native DAW, or you're with the terrorists." G.W. Busch Lite