I'm a professional graphic artist and work in the broadcast television field (local tv news). I don't know any 3d apps, but I do a lot of PhotoShop and After Effects work. All I can tell you if you want to get into this part of this field is to know those two the most. Knowledge of a 3d app is a plus, but many television stations can't afford to buy the app and all the goodies to go with it. A station I used to work for does use Lightwave.
If 3d modeling is your thing check into some broadcast design compaines. I have dealt with a few and all of them did do 3d work for graphic packages for local and national news shows as well as networks graphics and dvd stuff. Check out
this site and see what you could do.