I love Uncharted and MGS, they're two of my favourite all time series.
But looking at this, I think of them all, Halo has by far the most chance of making an interesting film, followed by Metal Gear Solid and then Uncharted.
The thing about Halo (and I don't even have a 360 never mind being a Halo fan) is that its actually got quite a cool aesthetic. Spartans look cool, there's lots of space for epic sci-fi shots, they have ring worlds. The four faction war is interesting material.
It would look good on a screen (if done right), make a very strong epic (which normally aren't character focused anyway) and it'd feel like it's bringing something new.
In contrast, MGS tries mainly to look like the real world. You could make a good film out of it, it'd be pretty easy to make a non-complicated storyline if you wanted, although the MGS mythos is confusing as, non of it is integral in the way that you couldn't make a film that didn't touch on it. Just make a cold-war badass spy film with a Metal Gear in it. What the franchise would bring to the table is the completely iconic look of Snake. It's nothing compared to the worlds of Halo, but the image of Snake would still be a good hook.
Uncharted would be like Prince of Persia, a good film, but in the end there's no solid Uncharted look. Uncharted looks like real life or adventure films, it doesn't look like Uncharted. So all Uncharted could be was the chance to make a Indianna Jones film. If they budget it, it could work and they might make a fantastic film which could become a successful series, but it wouldn't feel as connected to the games as the other two would