Mmm! Speculative fiction thread. You lucky Devils.

Dunno why, but once again the dark, dank recesses of my mind have dredged up a conversation once had on Warseer, or maybe even Portent.

In short, one poster was adamant that even a Space Marine Chapter couldn't take our planet - whether or not a miracle happened and the various armed forces all worked together. Now, I thought that was bunkum. I felt that the poster just wasn't taking into account how the Astartes wage war. I mean sure, in a stand up fight we've definitely got numbers on our side. Shame that a Chapter or even Strike Force would likely make good use of our complete lack of orbital defences, and promptly orbitallg bombard centres of military strength (Pentagon etc)

But it did get me thinking - how would we fare against the other races out there? And indeed Marines, no reason to leave them out

I'm hoping for fairly in depth posts here, rather than 'five Eldars kthxbai'