Install Kubuntu 10.04 directly instead of ubuntu + KDE desktop

I did the latter case first, but I encountered several following problems:

1. gcin input method floating window went dead when the desktop effects are enabled. The dead window made me unable to see which character to choose and it hid a random area on the screen. (It was proved later that this is an issue of gcin. gcin by now cannot function normally in the plasma theme. Installing Kubuntu directly cannot solve this issue)
   
2. Sometimes the background became back to Gnome background and there is no way to change it back rather than rebooting.
3. It is obviously slower than Kubuntu itself.
4. When the desktop effects are enabled, several kinds of windows cannot be displayed when using alt+tab to switch windows.
   

Hence it is not suggested to use both window managers on the same machine.

Here are some tweaks I did after installation kubuntu 10.04:

1. Disable Intel CPU c-state 3 and 4 to stop hissing. (see Ubuntu 9.04, 9.10, 10.04 Installation tweaks in Misc.)
2. Configure power manager of Thinkpad (see Ubuntu 9.04, 9.10, 10.04 Installation tweaks in Misc.)
   
3. Disable annoying kwallet
4. Configure terminal
5. Install KMess and disable online-offline notification
6. Enable desktop effects
7. Right click on the "K" start menu and launch menu editor to add Matlab after installing Matlab in command lines.
8. and many others...

After using Kubuntu 10.04 for a while, there are a couple of issues that I cannot solve so now I go back for Ubuntu 10.04...

1. Mic doesn't work. 
2. Wireless doesn't work. It seemed connected but only few packets are transmitted. In other words, it was not working properly.