As of Version 6.0, StylePrint has been superseded by Print[Style[expr, " style"]].
Since Version 3.0 (released in 1996), Subscripted has been superseded by RowBox, SubscriptBox, etc.
As of Version 6, SurfaceColor has been superseded by Specularity and Glow.
As of Version 6.0, SurfaceGraphics has been superseded by GraphicsComplex and related functionality.
Since Version 5.0 (released in 2003), TensorRank has been superseded by ArrayDepth.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(Obsolete Mathematica Symbol) TeXSave is superseded by Export[..., "TeX"] in Version 6.
As of Version 6.0, TextStyle has been superseded by BaseStyle, LabelStyle and other options.
ToASCII
(Obsolete Mathematica Symbol) Since Version 2.0 (released in 1991), ToASCII has been superseded by ToCharacterCode.
ToDate
(Obsolete Mathematica Symbol) ToDate has been superseded by functionality in DateList since Version 6.0.
As of Mathematica 7, ToFileName has been superseded by FileNameJoin.