Information update:

After taking a look at the code of kfontdialog.cpp i thought there might be a combination of TTF files that crashes kwrite, not a single TTF file. So i left only DISSOLVE.TTF in the ~/.fonts directory, chose "sugar [dissolve]" in the font choosing dialog => no crash; then i installed another font that appeared to be from the same font family (SUGAR.TTF as "sugar"), chose "sugar [dissolve]" => crash.

Created attachment 12386 [details]
TTF file combination that crashes kwrite

Well, the crash can be reproduced again and again. Therefore the two TTF files
(DISSOLVE.TTF and SUGAR.TTF) are attached (ttfs.tar.bz2). They can be copied
e.g. to ~/.fonts for testing purposes.

As you see, it already crashs in kdelibs/qt classes

An update with another system configuration:

Version:            (using KDE KDE 3.5.7)
Installed from:    SuSE RPMs
Compiler:          gcc (GCC) 4.1.2 20061115 (prerelease) (SUSE Linux) Target: i586-suse-linux Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib --libexecdir=/usr/lib --enable-languages=c,c++,objc,fortran,obj-c++,java,ada --enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.1.2 --enable-ssp --disable-libssp --disable-libgcj --with-slibdir=/lib --with-system-zlib --enable-shared --enable-__cxa_atexit --enable-libstdcxx-allocator=new --program-suffix=-4.1 --enable-version-specific-runtime-libs --without-system-libunwind --with-cpu=generic --host=i586-suse-linux Thread model: posix
OS:                Linux 


It still crashes with the fonts in ttfs.tar.bz2


Using host libthread_db library "/lib/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread -1230764336 (LWP 16928)]
[KCrash handler]
#9  0xb7553932 in bestStyle () from /usr/lib/qt3/lib/libqt-mt.so.3
#10 0xb755a7a6 in QFontDatabase::font () from /usr/lib/qt3/lib/libqt-mt.so.3
#11 0xb6e7834c in KFontChooser::style_chosen_slot ()
   from /opt/kde3/lib/libkdeui.so.4
#12 0xb6ec58f7 in KFontChooser::family_chosen_slot ()
   from /opt/kde3/lib/libkdeui.so.4
#13 0xb6ec5c4b in KFontChooser::qt_invoke () from /opt/kde3/lib/libkdeui.so.4
#14 0xb7591f1d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#15 0xb7592762 in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#16 0xb78de7f3 in QListBox::highlighted () from /usr/lib/qt3/lib/libqt-mt.so.3
#17 0xb766aaef in QListBox::setSelected () from /usr/lib/qt3/lib/libqt-mt.so.3
#18 0xb766712a in QListBox::mousePressEventEx ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#19 0xb7667534 in QListBox::mousePressEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#20 0xb75ca89e in QWidget::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#21 0xb75329c7 in QApplication::internalNotify ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#22 0xb7533909 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#23 0xb7bb8ca2 in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#24 0xb74d1f57 in QETWidget::translateMouseEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#25 0xb74d10ff in QApplication::x11ProcessEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#26 0xb74e198a in QEventLoop::processEvents ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#27 0xb75497f0 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#28 0xb75324ef in QApplication::enter_loop ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#29 0xb7718d75 in QDialog::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#30 0xb6201d93 in KateDocument::configDialog ()
   from /opt/kde3/lib/kde3/libkatepart.so
#31 0xb628896d in KateDocument::qt_invoke ()
   from /opt/kde3/lib/kde3/libkatepart.so
#32 0xb7591f1d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#33 0xb7592b5d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#34 0xb6e02239 in KAction::activated () from /opt/kde3/lib/libkdeui.so.4
#35 0xb6e408e2 in KAction::slotActivated () from /opt/kde3/lib/libkdeui.so.4
#36 0xb6f08fcd in KAction::slotPopupActivated ()
   from /opt/kde3/lib/libkdeui.so.4
#37 0xb6f09291 in KAction::qt_invoke () from /opt/kde3/lib/libkdeui.so.4
#38 0xb7591f1d in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#39 0xb78cd0ae in QSignal::signal () from /usr/lib/qt3/lib/libqt-mt.so.3
#40 0xb75adff7 in QSignal::activate () from /usr/lib/qt3/lib/libqt-mt.so.3
#41 0xb76980e7 in QPopupMenu::mouseReleaseEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#42 0xb6e0b58e in KPopupMenu::mouseReleaseEvent ()
   from /opt/kde3/lib/libkdeui.so.4
#43 0xb75ca880 in QWidget::event () from /usr/lib/qt3/lib/libqt-mt.so.3
#44 0xb75329c7 in QApplication::internalNotify ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#45 0xb7533909 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#46 0xb7bb8ca2 in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#47 0xb74d2859 in QETWidget::translateMouseEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#48 0xb74d10ff in QApplication::x11ProcessEvent ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#49 0xb74e198a in QEventLoop::processEvents ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#50 0xb75497f0 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#51 0xb7549686 in QEventLoop::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#52 0xb753257f in QApplication::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#53 0xb68a381f in kdemain () from /opt/kde3/lib/libkdeinit_kwrite.so
#54 0xb730a524 in kdeinitmain () from /opt/kde3/lib/kde3/kwrite.so
#55 0x0804e33f in launch ()
#56 0x0804ebca in handle_launcher_request ()
#57 0x0804ef4f in handle_requests ()
#58 0x0805014c in main ()

Some time ago I contacted Trolltech about this bug. Here's the tracker:

http://trolltech.com/developer/task-tracker/index_html?method=entry&id=172420

It seems to be fixed in QT 4.

Fixed according to comment #5.