The implementation of the Dinkumware STL (shipped with VS2005) is actually quite good. STL is a general-purpose library, so you can almost always write something better for very specific use cases.
I know about the following alternative implementations, but I never used them with VS2005:
SGI 3.3 Standard Template Library:
http://www.sgi.com/tech/stl/
STLport 5.1.6 (from SGI implementation):
http://www.stlport.org/
SGI, STLport / ==, . .
STL , , . , . , , - , STL.
Dinkumware STL , VS2005 ++.
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