First of all, I find the app great; I don't know yet whether it works well with my scanner, but I will definitely try it out (I usually access my scanner over its crappy HTTP interface) -- my scanner definitely shows up in the list, but it's off and I have nothing to scan right now (and I'm lazy).  Will try it out next time I do some expenses.  :-)

Is there a bzr branch for simple-scan where I could contribute fixes?  It has no Vcs-Bzr.  An upstream project to host tarballs for Debian would be nice too.

Description is way too short; I propose:
Description: GNOME scanning utility
 simple-scan is a GNOME simple scanning utility for photos, or text.
 .
 Scans may be cropped, rotated, and then either saved, emailed, or 
 printed.
 .
 simple-scan will work with all "SANE" supported scanners.

copyright is empty but should mention GPL.

I get this warning at runtime:
WARNING: Unhandled message: interface=org.freedesktop.DBus.Introspectable, path=/, member=Introspect

Would be nice to build with --as-needed or avoid the extra deps:
dpkg-shlibdeps: warning: dependency on libz.so.1 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libatk-1.0.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libfontconfig.so.1 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on librt.so.1 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libpthread.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libpango-1.0.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libgmodule-2.0.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libpangocairo-1.0.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libfreetype.so.6 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).
dpkg-shlibdeps: warning: dependency on libpangoft2-1.0.so.0 could be avoided if "debian/simple-scan/usr/bin/simple-scan" were not uselessly linked against it (they use none of its symbols).

.pot is updated during build, so that's fine.

Please build-dep on gconf2 for gconftool-2 (AM_GCONF_SOURCE_2).

Would be nice to subscribe the desktop team bug contact to simple-scan, and/or Robert.

Using Debian version numbers with lucid uploads when the package is also in Debian sounds like a very bad idea.  Different 0.8.1-1 were uploaded to lucid and Debian.  copyright file was apparently fixed in Debian already.