Vertical alignment in tabular cells with variable height

The vertical adjustment of the row "c" is related to the definition of the columntype X which uses the specifier p.

You need m for a centered adjustment and b for bottom. This can be achieved by \multicolumn, whereby the line width must be saved (I don't know a good solution).

Here is an example:

\documentclass{article}
\usepackage[a4paper]{geometry}
\usepackage{tabularx}
\usepackage{lipsum}
\begin{document}

\begin{tabularx}{\textwidth}{ | X | c | }
  \hline
  \lipsum*[1]\xdef\tempwidth{\the\linewidth} & top\\\hline
  \multicolumn{1}{|m{\tempwidth}|}{\lipsum*[1]} & center\\\hline
  \multicolumn{1}{|b{\tempwidth}|}{\lipsum*[1]} & bottom\\\hline
\end{tabularx}
\end{document}

\documentclass{article}
\usepackage[a4paper]{geometry}
\usepackage{tabularx}
\usepackage{lipsum}
\begin{document}

\noindent
\begin{tabularx}{\textwidth}{ | X | c | }
  \hline
  \lipsum[1] & top\\
  \hline
  \noindent\parbox[c]{\hsize}{\lipsum[1]} & center\\
  \hline
  \noindent\parbox[b]{\hsize}{\lipsum[1]} & bottom\\
  \hline
\end{tabularx}

\end{document}

Another way, using a minipage environment instead of a tabularx package:

\documentclass{article}
\usepackage{lipsum}
\usepackage[a4paper]{geometry}
\begin{document}

\begin{tabular}{|l|c|}
  \hline
  \begin{minipage}[t]{0.85\textwidth}\lipsum[1]\end{minipage} & top\\
  \hline
  \begin{minipage}{0.85\textwidth}\lipsum[1]\end{minipage} & center\\
  \hline
  \begin{minipage}[b]{0.85\textwidth}\lipsum[1]\end{minipage} & bottom\\
  \hline
\end{tabular}

\end{document}