Is there a way to enter the absolute (not relative) value of a transformation? When I press G, R, or S and enter a number, Blender will move, rotate, or scale the selection relative to its local value.  Is there a way to press, say R > 4 > 5, and then some other key to have it set the absolute rotation to 45° instead of incrementing it by 45°?  I know how to go into the object properties or right hand toolbar and set the position, rotation, and scaling there, I am wondering if there is a keyboard way to do it (as there is for most everything in Blender).
Not entirely the answer you're looking for, but at least for some cases it works nicely to do one or more of the following:


Object > Clear > Location  Alt+G
Object > Clear > Rotation  Alt+R
Object > Clear > Scale     Alt+S


And after that make the transform and input the desired value. 

Also, it's important to mention that after pressing move G, rotateR or scale S, you can define:


global axis by pressing X,Y or Z
local axis by pressing XX, YY or ZZ.