For your first skis it doesn't really matter. Get whatever's cheap in the ski shop but not some total piece of shit. Personally, I'd recommend shorter skis to start because their easier to spin and do general tricks with. As you progress, you'll have a better idea of what kind of skis you want.
I would recommend something along the lines of the Armada El Reys, Bluehouse Mr's, or like you said the Ar7's....because of your racing background, all those skis will carve and provide ample all mtn. capability and are all fairly stiff. I personally have the El Reys and they carve great, (have them mounted center or darn close, you wont regret it.)
-Couple of advil, relax and chill, at a standstill with how bad I feel
What is that thing? It looks like one of those giant moles from Super Mario World. -Casual
3. Full tilts will make your dick grow 4"-5" (it's debated)
I ride K2 Dissorderlys and I have to say they're a really great pair of skis for doing both park features and carving. They have a solid wood inner core and they're somewhat flexible and somewhat stiff. By far the best pair of skis I've had.