I think Xfire would be one of the better options, as you can adjust the binding used to take a screenshot. and it offers you a place to upload the screenshots to.
I've taken multiple screenshots in Fallout3 using that method without hopping in and out of game ....... they get saved in the Fallout3 folder. Wouldn't Deadspace do the same?
I would recommend fraps. Its a small download and is a very trim and neat little app. Its primary use is displaying framerates in games and benchmarks, but it also does a great job of taking screens.