During a Q & A at CineEurope, Kevin Feige was asked what movie was the most important movie Marvel had coming and his answer was DOCTOR STRANGE. He has expressed his love for the good Doctor before and the need to introduce
"a whole other side of the Marvel comics, which is that supernatural side - the inter-dimensional side of the Marvel universe, and Doctor Strange is, I believe, our entry point into that other realm, which has dozens of characters and story-lines all of its own."
But during the above mentioned Q&A, Feige went further:
Feige at CineEurope:
DOCTOR STRANGE is '“very, very important, not just because it's an amazing character study, and a journey of a man who's gone from this very arrogant surgeon to somebody who is quite zen and literally keeps all of reality together on a daily basis, but it also is going to open up a whole other side of storytelling for our movies.”
All of this is true, but I think there is one word in that whole comment that is telling and may give us a key as to what to expect when it comes to Strange's connection to the whole 'Infinity Guantlet' story-line. And that word is REALITY.
Feige could possibly have tipped his hand as to the direction of the Doctor Strange movie and what Infinity Gem would be involved. If this comment is to be taken seriously, it looks like it could be the REALITY GEM.
Allows the user to fulfill wishes, even if the wish is in direct contradiction with scientific laws. Occasionally stated to be the most 'dangerous' of the Gems if wielded without the other Gems to keep its reality-altering powers from accidentally surging out of control. During the storyline where The Hood had control of the object, it at one point rapidly cycled through multiple alternative universes (apparently showing its ability to not only control reality, but travel to and through different realities as well).
The fact of the matter is that Stephen Strange, working as the Sorcerer Supreme, deals in a myriad of inter-dimensional realities that none of the other Marvel Characters even come close to. Where we find the Power Gem hidden deep inside a dark world somewhere in Thor's Nine Worlds; One of the innumerable dimensions that Strange deals with would be perfect to hide one of the gems. And, seeing as Strange deals in holding Reality together, it may make sense to include the REALITY GEM in the Doctor Strange movie.
But, although this comment seems to make all of this viable, to be honest, the number one contender for the Doctor Strange Movie is the SOUL GEM. This is mainly because Strange has owned the SOUL GEM in comic Canon.
The Soul Gem is sentient; it has a desire to collect souls
The gem can attack another's soul in various ways
The gem can reveal information by peering into another's soul or using the 'Cold Light of Truth'
The gem can trap souls inside itself in an idyllic world.
The gem's wielder can access the memories and skills of those imprisoned within Soul World
The gem can revert beings to their natural state.
The gem protects its wielder from soul-based attacks.
The gem can disrupt the anima of a soul with a karmic blast rendering the target temporarily unconscious. Certain beings are immune to this attack.
I don't see how you can deal with the SOUL GEM and not Adam Warlock. So, I see Warlock being involved also.
BUT, is this enough? Considering this, I still think the Reality Gem is a strong contender and could include a Reality bending witch aka THE SCARLET WITCH.
Allows the user total control over the past, present and future. Allows time travel, can age and de-age beings and also be used as a weapon by trapping enemies or entire universes in unending loops of time. Also at full potential grants Omniscience.
But, just to muddy the waters, there is a story-line they could pull out from MARVEL PREMIERE #13-14 that could make the TIME GEM a possibility.
In this story, a time traveling Sorcerer Supreme from the future appears to absorb all of the magical energies from all times and thus become god. But this is definitely a long shot.