The rotation should match what you had in Blender. Make sure that your view in Blender isn’t tilted. Use the grid to determine which way is up. Also note the Y axis for your model. In Unity Y is up and down while the Z axis is sometimes used for this on certain models. Ideally this would be fixed in your model itself but you can also use an empty game object as the parent. Here is a more in depth look at this issue: http://docs.unity3d.com/Manual/HOWTO-FixZAxisIsUp.html
Note that this SHOULD be fixed when exporting an FBX file from Blender into Unity. While Blender does use the Z axis for up and down, when you bring it into Unity it’s “converted” and now uses the Y axis for up and down while keeping the same rotation values as the original.
