Drawing beautiful block diagrams in LaTeX

I used to put together the illustrations in my publications with a mixture of Inkscape, CorelDraw and psfrag, but obviously this couldn't continue for a long time without becoming an insult to graphic design.

For my latest writings I am returning to the basics: PSTricks. (I know there are lots of other programs to draw block diagrams, but I didn't find any that allowed enough customization). To avoid starting from zero, I am using the PSTricks Signals and Systems package (pst-sigsys), which is easy to customize if you keep the PSTricks user guide (pdf) at hand.

Here's a simple example:

\documentclass{article}
\usepackage{pst-sigsys}

\pagestyle{empty}

\begin{document}

\begin{figure}[ht]
\centering %
\begin{pspicture}[showgrid=false](0.5,-1.2)(9,1.55)
%--- Define blocks ---
\rput(0.5,0){\rnode{s}{$s[n]$}}
\dotnode[dotstyle=square*,dotscale=0.001](1.7,0){dot}
\psblock(3,.75){H1}{$H_1(z)$}
\psblock(3,-.75){H2}{$H_2(z)$}
\psblock(5.8,.75){B2}{$\hat H_2(z)$}
\psblock(5.8,-.75){B1}{$\hat H_1(z)$}
\pscircleop(7.7,0){ominus}
\rput(9,0){\rnode{e}{$e[n]$}}

%--- Connect blocks ---
\psset{style=Arrow}
\ncline[nodesepA=.15]{-}{s}{dot}
\ncangle[angleA=90,angleB=180]{dot}{H1}
\ncangle[angleA=-90,angleB=180]{dot}{H2}
\ncline{H1}{B2} \naput[npos=.5]{$x_1[n]$}
\ncline{H2}{B1} \naput[npos=.5]{$x_2[n]$}
\ncangle[angleB=90]{B2}{ominus} \naput[npos=.5]{$z_1[n]$}
\ncangle[angleB=-90]{B1}{ominus} \naput[npos=.5]{$z_2[n]$}
\ncline[nodesepB=.15]{ominus}{e}
\end{pspicture}
\end{figure}

\end{document}

which, after some retouching of the .sty file produces this pretty diagram:



Update 6th December 2009: Here's a slightly more complicated diagram, based on the same codes as the above example.