Yesterday I let aptitude upgrade KDE from version 3 to 4.

It's all in now, it wasn't painless but it went in mostly okay. Lots of things don't work and quite a few applications crash constantly or run like treacle. It's pretty but it's as yet unstable and unfinished. I think Debian was wise to release Lenny with KDE3, by the time Squeeze comes out KDE4 will be feature complete and stable.

I think I'd have been better not allowing it to upgrade my KDE3 settings to KDE4 and simply started with all new KDE4 and vanilla defaults. My customised KDE3 settings did not migrate cleanly too KDE4. Also my old AMD64 2GHz CPU and Nvidia FX graphics card is not up to the job of all the eye candy.