Version:            (using KDE 4.2.1)
Compiler:          GCC 4.3.3 target: x86_64-pc-linux-gnu
OS:                Linux
Installed from:    Gentoo Packages

I had 1 konqueror window open, 1 konsole window open, 1 firefox window open and the XFCE4 packages were being built in the konsole window using Gentoo's package build system, Portage. Luckily, I have configured kde to build with debug flags AND preserve debug information, so am able to paste the following backtrace:

Application: KDE Daemon (kded4), signal SIGSEGV
0x00007f03a80bd901 in nanosleep () from /lib/libc.so.6
Current language:  auto; currently c

Thread 1 (Thread 0x7f03acb36750 (LWP 2550)):
[KCrash Handler]
#5  0x00007f03ab249a06 in QString::operator== (this=<value optimized out>, other=@0x7fffb4b71d90) at ../../include/QtCore/../../src/corelib/tools/qstring.h:104
#6  0x00007f03ac3b2b86 in KDirWatchPrivate::inotifyEventReceived (this=0x2331cf0) at /var/tmp/portage/kde-base/kdelibs-4.2.1/work/kdelibs-4.2.1/kio/kio/kdirwatch.cpp:298
#7  0x00007f03ac3b2ea8 in KDirWatchPrivate::qt_metacall (this=0x2331cf0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffb4b72010)
    at /var/tmp/portage/kde-base/kdelibs-4.2.1/work/kdelibs_build/kio/kdirwatch_p.moc:75
#8  0x00007f03ab300085 in QMetaObject::activate (sender=0x2262f80, from_signal_index=<value optimized out>, to_signal_index=4, argv=0x770065006e002e) at kernel/qobject.cpp:3057
#9  0x00007f03ab33482e in QSocketNotifier::activated (this=0x0, _t1=10) at .moc/debug-shared/moc_qsocketnotifier.cpp:83
#10 0x00007f03ab305543 in QSocketNotifier::event (this=0x2262f80, e=0x7fffb4b72600) at kernel/qsocketnotifier.cpp:316
#11 0x00007f03a9e321ad in QApplicationPrivate::notify_helper (this=0x2268ed0, receiver=0x2262f80, e=0x7fffb4b72600) at kernel/qapplication.cpp:4084
#12 0x00007f03a9e3ad9e in QApplication::notify (this=0x7fffb4b72920, receiver=0x2262f80, e=0x7fffb4b72600) at kernel/qapplication.cpp:4049
#13 0x00007f03abe7a021 in KApplication::notify (this=0x7fffb4b72920, receiver=0x2262f80, event=0x7fffb4b72600)
    at /var/tmp/portage/kde-base/kdelibs-4.2.1/work/kdelibs-4.2.1/kdeui/kernel/kapplication.cpp:307
#14 0x00007f03ab2ea73b in QCoreApplication::notifyInternal (this=0x7fffb4b72920, receiver=0x2262f80, event=0x7fffb4b72600) at kernel/qcoreapplication.cpp:598
#15 0x00007f03ab312ba9 in socketNotifierSourceDispatch (source=0x226b590) at kernel/qcoreapplication.h:213
#16 0x00007f03a5b8087a in IA__g_main_context_dispatch (context=0x226b440) at gmain.c:2144
#17 0x00007f03a5b8402d in g_main_context_iterate (context=0x226b440, block=1, dispatch=1, self=<value optimized out>) at gmain.c:2778
#18 0x00007f03a5b841eb in IA__g_main_context_iteration (context=0x226b440, may_block=1) at gmain.c:2841
#19 0x00007f03ab31292f in QEventDispatcherGlib::processEvents (this=0x22690e0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:323
#20 0x00007f03a9ebfe4f in QGuiEventDispatcherGlib::processEvents (this=0x0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#21 0x00007f03ab2e93a2 in QEventLoop::processEvents (this=<value optimized out>, flags={i = -1263065056}) at kernel/qeventloop.cpp:149
#22 0x00007f03ab2e9535 in QEventLoop::exec (this=0x7fffb4b72860, flags={i = -1263064976}) at kernel/qeventloop.cpp:196
#23 0x00007f03ab2ee1fe in QCoreApplication::exec () at kernel/qcoreapplication.cpp:880
#24 0x00007f03ac74c597 in kdemain (argc=1, argv=0x7fffb4b72c08) at /var/tmp/portage/kde-base/kdelibs-4.2.1/work/kdelibs-4.2.1/kded/kded.cpp:937
#25 0x00007f03a803c5c6 in __libc_start_main (main=0x400960 <main>, argc=1, ubp_av=0x7fffb4b72c08, init=0x400990 <__libc_csu_init>, fini=<value optimized out>, rtld_fini=<value optimized out>, 
    stack_end=0x7fffb4b72bf8) at libc-start.c:226
#26 0x0000000000400899 in _start ()

I'm also appending a portion of the emerge --info information. while much of this is only of relevance to Gentoo, there are several pieces of information that might be relevant to the bug fixers. Thanks for you guys' work on KDE, it's awesome. 

satori ~ # emerge --info                                                                                                                                       
Portage 2.1.6.7 (default/linux/amd64/2008.0, gcc-4.3.3, glibc-2.9_p20081201-r2, 2.6.28-gentoo-r3 x86_64)                                                       
=================================================================                                                                                              
System uname: Linux-2.6.28-gentoo-r3-x86_64-Intel-R-_Core-TM-2_Duo_CPU_E8200_@_2.66GHz-with-glibc2.2.5                                                         
Timestamp of tree: Wed, 11 Mar 2009 06:00:02 +0000                                                                                                             
ccache version 2.4 [enabled]                                                                                                                                   
app-shells/bash:     4.0_p10                                                                                                                                   
dev-java/java-config: 2.1.7                                                                                                                                    
dev-lang/python:     2.5.4-r2                                                                                                                                  
dev-util/ccache:     2.4-r8                                                                                                                                    
dev-util/cmake:      2.6.3                                                                                                                                     
sys-apps/baselayout: 2.0.0                                                                                                                                     
sys-apps/openrc:     0.4.3-r1                                                                                                                                  
sys-apps/sandbox:    1.4                                                                                                                                       
sys-devel/autoconf:  2.13, 2.63                                                                                                                                
sys-devel/automake:  1.5, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10.2                                                                                                 
sys-devel/binutils:  2.19.1                                                                                                                                    
sys-devel/gcc-config: 1.4.1                                                                                                                                    
sys-devel/libtool:   2.2.6a                                                                                                                                    
virtual/os-headers:  2.6.28-r1                                                                                                                                 
ACCEPT_KEYWORDS="amd64 ~amd64"                                                                                                                                 
CBUILD="x86_64-pc-linux-gnu"                                                                                                                                   
CFLAGS="-march=core2 -O2 -pipe -g -ggdb"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/share/config /var/lib/hsqldb"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo /etc/udev/rules.d"
CXXFLAGS="-march=core2 -O2 -pipe -g -ggdb"
DISTDIR="/usr/portage/distfiles"
FEATURES="ccache distlocks fixpackages parallel-fetch protect-owned sandbox sfperms splitdebug strict unmerge-orphans userfetch"
GENTOO_MIRRORS="http://gentoo.gg3.net/ "
LDFLAGS="-Wl,-O1"
LINGUAS="en hi hi_IN"
MAKEOPTS="-j3"