Blender used by game designers? I hope this question is relevant to this forum...I've had a lot of incredible help from people on this site and it's always been appreciated.  I actually just have a general question: is Blender ever used by large game companies or is it sort of like how GIMP is never mentioned for graphic design jobs but Photoshop is always a must?  

I'm thinking about getting into 3d modelling professionally and I love Blender.  So I guess I'm wondering if it is necessary to have to learn more commercial, expensive programs as well?

Thanks!
No, Blender has not been used by any big game companies to create games, and no well-known games have been created with Blender. (Unless I missed them.)

However, as an experienced game developer myself, I can tell you that many have used Blender for 3D modelling, and exporting the models into other game development tools such as Unity to create games using their 3D models.

If you're thinking of getting into game development I would recommend you join gamedev.stackexchange.com, and perhaps start off with a couple of YouTube tutorials on how to use Blender and Unity (or other software) jointly.