keep in mind that one person's definition of a "good all-mountain" ski is gonna differ drastically from anothers.
also keep in mind that quite a lot of folks frown upon the catch-all term "all-mountain" ski.
1. if you are a competent skier then you should be able to turn any ski into an all-mountain ski
2. no ski will ski the whole mountain...each ski tends to excel in different areas. but if you re-visit #1 above, it shouldn't matter.
3. everybody's idea of an all-mountain ski will differ. for example i use a Lib-Tech NAS Freeride (93/99mm alternating underfoot) as my every day ski. Some on this forum will advocate skinnier planks (in the 78mm - 90mm range) as good for all-mountain. Others will advocate fatter planks (in the 90mm - 100mm range). No one will be absolutely right or wrong in their suggestions as they are the right ski for the person in question.
That said, some skis that tend to pop up as good "all-mountain" skis are:
The PMGear Bro (I have a number of friends who ride this every day and then have a super fat pair of skis for deep pow days).
K2 Public Enemy
AK King Salmon (this was my every day ski before the Lib Tech)
Volkl Gotama and the aforementioned Mantra
And of course the Lib-Tech NAS Freeride (or you could try their park ski, which has a mid-80's footprint).
Again, you might want to consult some of the gear guides (SKI Magazine, Skiing, SkiPress, Powder, etc) for additional material, as well as Realskiers online.
Best of luck,
and as Maggot suggested, use the "Search" function. That's what it's there for.