The fact that I didnt have such issues on any other machine made me think that there was something seriously wrong with my laptop.
KDE+QT were compile with the same CFLAGS+USE flags on every machine and he kde+qt4 versions were exactly the same. So, I figured out that it has to be something related to graphics card ( or drivers ).

KDE4 ( with qt-4.5 ) was running smoothly on every pc with Nvidia graphics card. But my laptop has Intel graphics chipset and Qt-4.5 sucked big time.

This is my hardware

0:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 03)

So , after some googling , I did the below changes

1) Xorg.conf

Added the following on Device Section

Option “DRI” “true”
Option “AccelMethod” “XAA”
Option “XAANoOffscreenPixmaps” “True”
Option “XaaNoPixmapCache”

2) .bashrc
Added the following on my bashrc file

export INTEL_BATCH=1

Since then, my kde4 runs perfectly with Qt-4.5 . No corrupted layouts or unreadable fonts anymore , plus it is so much faster.

So, give it a try if you are having a hard time with Qt-4.5 + Intel graphics card