Unless you're into sliding around backwards I'd stick with a traditional shape for your stated purpose. If you do end up going with a twin tip, for whatever reason, size up one length to allow for the raised tail - you lose around 8-10cm of effective running length depending on the ski.
Opinions vary, of course, but the skis that stand out in the space you're interested in are the following:
Kastle MX78 or MX83 - traditional shape, flatish tail, no early rise, elliptical sidecut (tighter in the front, getting wider through the tail)
Kastle FX84 - lighter metal in this model, a slightly different shape
Kastle LX82 - lighter feeling than the MX, single radius sidecut
Blizzard Magnum 8.1 - traditional shape, flatish tail, no early rise
Blizzard Magnum 8.5 - newer model, incorporates early rise
Head Supershape Titan
Volkl's RTM series - per the above
Dynastar's Outland series is getting great reviews - various models and widths; has early rise in the tip and a short turning radius on hardpack; read some reviews as you might be able to go longer with this one
Rossignol's Experience series
Salomon's Enduro series
Atomic's VF series
Fischer's Progressor 1000, or the Motive series
I'm probably just confusing you now with all the above. Of these the Kastles are considered top of the class by many in the industry (read some reviews) although you can pay big $$$ for them. I own the MX78 (and have taken a couple of demo runs on the 83) and they're easily the best consumer all mountain skis I've ever slid around on. I've skied examples of all the above except the Salomons/Fischers, and I've included them for the hell of it.
It always, always pays to demo of course, but hopefully the above might give you some models to target at your nearest demo day. Still, Holiday is selling a 172cm Blizzi Magnum 8.1 in great shape on the gear sales board (second page now). That may be a little long for your taste. Peruse the board anyway as there's often deals on offer.
Good luck with the coming season. Come back and post to let us know what you end up with and how you like them.
Edited by sinbad7 - 10/28/12 at 3:54pm