For simple 3D modelling (and just the modelling, mind), I've become very much a fan of Wings3D. Ignoring the geeky bias I might have because it's written in Erlang, it has a very shallow learning curve and, in combination with Blender, you should be able to get some usable renders pretty quickly.

If you want to go witth straight-up 2D, though, I've found it fairly easy to get simple and stylish results from Inkscape. That way might be better anyway - why do what everyone else is doing?

Either way, I'd recommend just throwing something together quickly until you've got a good 'working model' - then you can either spend a bit more time on the graphics, or consult someone who knows their way around a wacom!