Data presentation applications

Desktop

Google Earth - Single layer type 

World Wind - WMS supported, any server any image

_Spherical VIEWERS- 

Science On a Sphere - NOAA

The Magic Planet - Global Imagination

Globe4D - Leiden University

OmniGlobe - ARC Science Simulations

OSSIM is making a lot of progress lately and can use drag and drop imagery placement. It can even use World Wind as a UI/front end with some tweaking.