Yeah, I don't think Marathon and Destiny take place in the same universe either. Bungie will almost certainly throw Marathon references in there for the hell of it, but I think they're separate worlds. (It should be interesting to see how they handle Halo references, though.)

I don't even know how that would work since by 2700 the Marathon would be about 7 or 8 lightyears from Earth. Also, it's never quite said (except in the final screen of Marathon 2*) what sort of shape the UESC is in during the actual battle of Tau Ceti, but it's implied they're still in very good shape with MULTIPLE Terran cities and colonies throughout Sol. [quote]**[i] "It was ten thousand years before fate brought Durandal once again into contact with man... When Durandal returned to Sol it was not with the captured Khfiva but in a Jjaro dreadnought he called Manus Celer Dei. What he learned of the Jjaro he told no one, saying only that he had stopped by to assure that Earth did not forget him. Nor will it soon, the way he tied the Guard in knots around Pluto before folding directly into a low-Earth orbit."[/i][/quote] The Guard designation implies that Human government is very much in good shape even in 10,000 years. Maybe I'm reading into it wrong, but I assume Destiny's humans are sort of on their last legs.