Most of our modelling is done using Rhino 4 with rendering in Flamingo.
Rhino is excellent for most geometric 3D work, while Flamingo provides a fine balance between speed and quality on rendered images, particularly with the benefit of layering and post production in Photoshop.
When projects require specialized lighting effects, material rendition, or animation we use Cinema 4D R10, and Vue X Stream when landscaping effects are a critical consideration.
We also use Adobe Photoshop for post production and Okino Polytrans for large file format conversions.
Let's not forget Traditional rendering (no software here) I choose to work in a variety of media depending on the requirements of the job.
Currently I rely on Staedtler Pigment Liners and Pilot Hi-Techpoint V5s for all my Pen and Ink work, and currently use Pantone Tria Inks for a great deal of my colour rendering. Detailing is normally done using Winsor and Newton gouache.
All our developed rendering work is finetuned to varying degrees in Photoshop CS using a Wacom A3 Tablet.