The "one ski quiver" is the holy grail of most skiers (and ski retailers for that matter). I have been searching for quite some time now, and have pretty much convinced myself that there isn't one ski that does everything well. Sierra Jim has it right when he tells someone to define priorities and and consider trade-offs of different designs. I have skiied a ton of different skis in the "everyday driver" category trying to find something with the balance of skills that I am looking for, I like a lot of those skis, but all have definite strengths and weaknesses, and it all boils down to an individual's priorities.
Here is a list of skis that I have skiied a lot and put into the "one ski quiver" category:
( Me: middle aged, 6'1" - 230#, been skiing for over 35+ years, probably level 8+/-, ski mostly in the northern Rockies and Utah.)
Fischer Watea 84 - 184cm - Very versatile, does well both on and off piste, good in bumps, good edge hold on everything short of ice or very hard snow. Not great float in pow or heavy crud, gets a little nervous and chattery on hard snow.
Fischer Watea 94 - 178cm -Vvery similar to 84, but more stable at speed, not super in bumps, but ok, still not great on ice or hard snow. Crud stability and powder performance isn't as good as I would like - maybe would be better in a 186cm.
Head Peak 78 - 177cm - A lot has been said about this ski, fairly quick and easy to ski, to me it doesn't feel as beefy as many have described, it holds and edge decently, but not great on hard snow, crud and pow performance just average. Not spectacular at anything, but passable in most conditions.
Fischer Cold Heat - 176cm - Very strong carver, with a lot of power in and out of the turn, but not as damp as I would like, and I find it a bit twitchy and overreactive at times. Great on piste, average off piste, doesn't float well, just blasts through things. A little stiff torsionally for bumps.
Volkl AC50 - 177cm - Very similar to Fischer Cold Heat, but more damp and smooth. Really good on-piste, but "digs in" too much to be fun off piste, doesn't float at all even with its width.
Rossignol Phantom SC87 - 178cm - Very damp, smooth ski, very stable at speed. But, carving ability is just average, requires a lot of skier imput and a bit of steering. Not terribly quick from edge to edge. Crud performance is good, but more of a blaster than floater, it also dives in pow. Best for off-piste, ok on soft groomers, not so much on hard snow or ice.
Stockli Stormrider XXL - 178cm - Very smooth, damp ski, that is good off-piste, just an average carver and just average on groomed or hard snow. Kind of lifeless compared to most typical Stockli's.
The thing that I have found is that these skis all lack the carving performance, precision and quickness of a narrower waisted ski on groomed runs. I much prefer a carving ski like a Fischer Progressor 9 or Stockli Laser Cross Pro for hard and groomed conditions. When there is 6" or more of new snow or crud, I prefer a 100mm waisted ski, like the Fischer Watea 101, Volkl Gotama, or Line Prophet 100, they handle the loose conditions so well. These middle of road, one ski quiver, skis do a lot of things well, but nothing great, and I find myself always wanting more from them on any given day. So in my opinion, a perfect one ski quiver doesnt' exist.