Maya+Max are absolute kings, everybody is using them. My vote went for Houdini though because Houdini is the sweetest package there is - although used mainly for effects, not visualizations. Also, built in renderer, Mantra, is pretty sweet.
By supporting Maya you would challenge Arnold which would be hard as everyody is using Arnold with Maya. For Houdini it's even worse.
So maybe you should introduce the support for the "funny" stuff if you want to make the most moneyz (Sketchup/Rhino/Revit)? There is no other real competition for you for those aside VRay. I personally use 3ds max the most, although due to the nature of my work, i use all 3d packages really.
Why so many modo votes? it's so unreliable! I'm shocked by modo's position in the list :)