Alright, I just figured it all out after browsing the non-PC sections at OkaySoft.de a minute ago.
There exists a DXHR release called "Augmented Edition", BUT it's for PS3 and Xbox360 only, not for PC! And I'm only interested in PC versions.
Here are all the correct names of the releases, language versions and platforms I figured out:
Deus Ex Human Revolution (PC, PS3, Xbox360 in Germany/UK)
Deus Ex Human Revolution Limited Edition (PC only in Germany/UK)
Deus Ex Human Revolution Collectors Edition (PS3 and Xbox360 only in Germany/UK)
Deus Ex Human Revolution Augmented Edition (PS3 and Xbox360 only in Germany/UK)
So yeah, it's clear. Limited Edition is the one to go for us PC users!
And for all you PS3 and Xbox360 users out there, the Augmented Edition is the one, as you have already voted for in James' poll above.
Funny and confusing at the same time, isn't it, that the DXHR publishers call the PC releases differently. I should keep that in mind for the future that special PC editions of games may not have the same names as PS3 or Xbox360 editions.