To simplify, treat i.e., and e.g., as full fledged citizens of the English language as they are in the dictionary. See also http://english.stackexchange.com/questions/3911/correct-spelling-italicization-of-e-g-i-e

sample-book.tex

@@ -98,8 +98,6 @@
 \newcommand{\hairsp}{\hspace{1pt}}% hair space
 \newcommand{\hquad}{\hskip0.5em\relax}% half quad space
 \newcommand{\TODO}{\textcolor{red}{\bf TODO!}\xspace}
-\newcommand{\ie}{\textit{i.\hairsp{}e.}\xspace}
-\newcommand{\eg}{\textit{e.\hairsp{}g.}\xspace}
 \newcommand{\na}{\quad--}% used in tables for N/A cells
 \providecommand{\XeLaTeX}{X\lower.5ex\hbox{\kern-0.15em\reflectbox{E}}\kern-0.1em\LaTeX}
 \newcommand{\tXeLaTeX}{\XeLaTeX\index{XeLaTeX@\protect\XeLaTeX}}
@@ -291,7 +289,7 @@ Introduction & \hangp{7} & \hangp{9} & \hangp{9} & 9 \\
 \bigskip
 The design of the front matter in Tufte's books varies slightly from the
 traditional design of front matter.  First, the pages in front matter are
-traditionally numbered with lowercase roman numerals (\eg, i, ii, iii,
+traditionally numbered with lowercase roman numerals (e.g., i, ii, iii,
 iv,~\ldots).  Second, the front matter page numbering sequence is usually
 separate from the main matter page numbering.  That is, the page numbers
 restart at 1 when the main matter begins.  In contrast, Tufte has
@@ -851,7 +849,7 @@ also cause the graphics to be replaced by outlines.
 The \docclsoptdef{nofonts} option prevents the \TL classes from
 automatically loading the Palatino and Helvetica typefaces.  You should use
 this option if you wish to load your own fonts.  If you're using \tXeLaTeX, this
-option is implied (\ie, the Palatino and Helvetica fonts aren't loaded if you
+option is implied (i.e., the Palatino and Helvetica fonts aren't loaded if you
 use \tXeLaTeX).  
 
 The \docclsoptdef{nols} option inhibits the letterspacing code.  The \TL\