If you're just gonna get one ski, then you're gonna want a really versatile ski. We have a huge amount of terrain over here and conditions really can vary so much.
where abouts you heading and what do you prefer, a stiff or soft ski?
Summat with a fairly wideish waist should be good, like 90-96
A few good options might be:
4frnt MSP
Armada ARV
Rossi Scratch BC (not clued up on the names this year - rastafarider should know?)
Head mojo 90
Salomon teneighty Gun
K2 Seth
I knwo these are all different skis, so bag on me. i'm just putting a few out there.
Also, what's wrong with just the AR6? As an everyday ski he's gonna be sweet as, then if it dumps, which we all know doesn't happen as often as we'd like, he could just rent.  If he's traveling around and stuff it makes sense to me.