AlienBrain

From Avid:

Alienbrain is a digital asset management system for artists in the entertainment industry

• Commercial (more expensive than Perforce), centralized
• Designed to integrate with other professional 2D and 3D workflow tools such Photoshop, Maya, 3ds Max, Microsoft Visual Studio, etc.

I have no experience with AlienBrain, and only heard about it from the book Game Coding Complete by Mike McShaffry. He appears to think highly of it, however:

Artists and other contributors will actually use this product, unlike others that are mainly designed to integrate well with Visual Studio and not creative applications such as Photoshop and 3D Studio Max. One of the big drawbacks of other products is their rather naive treatment of nontext files. AlienBrain was written with these files in mind.

Of course he also describes it as:

For those of you with really serious asset tracking problems and equally serious budgets...