As of Version 6.0, ShortestMatch has been superseded by the pattern object Shortest.
Since Version 5.0 (released in 2003), SingularValues has been superseded by SingularValueList and SingularValueDecomposition.
Since Version 2.0 (released in 1991), StartProcess has been superseded by Install and MathLink.
Since Version 3.0 (released in 1996), Subscripted has been superseded by RowBox, SubscriptBox, etc.
As of Version 6, SurfaceColor has been superseded by Specularity and Glow.
As of Version 6.0, SurfaceGraphics has been superseded by GraphicsComplex and related functionality.
Since Version 5.0 (released in 2003), TensorRank has been superseded by ArrayDepth.
TeXSave
(Obsolete Mathematica Symbol) TeXSave is superseded by Export[..., "TeX"] in Version 6.
ToASCII
(Obsolete Mathematica Symbol) Since Version 2.0 (released in 1991), ToASCII has been superseded by ToCharacterCode.
Since Version 3.0 (released in 1996), ToHeldExpression has been superseded by ToExpression.