after some time of pondering, I finally made my mind up to get some more current hardware. My config now is :
* intel core2duo e6300 + sonic tower + s-flex/800rpm/120mm
* asus p5k crossfire mainboard
* 2*1GB Team DDR2-6400 Memory
* Gigabyte X1650 Pro/256MB GDDR3/silent pipe II
* Gigabyte X1600 Pro/256MB GDDR2/silent pipe
* 250GB Samsung Spinpoint S-ATA 2
* 500GB Samsung Spinpoint S-ATA 2
* Win XP SP2
Sure this is not bleeding edge (rather budget level), but is a good treat for my needs.
The greatest benefit of all is changing to a 2 Harddisk setup: I do a lot of installing from image files, which can be time consuming when you have your images on the same physical disk as your install target. with 2 Sata2-drives, I managed to install a full 700Megs image in a few seconds. Physically separating soundlibs and temporarily generated audio is also a great advantage for recording, as I have read.
I haven't received my second VGA Adapter yet, I'm really interested in seing how crossfire works (Well, my setup is not optimised for games anyway, with the slower X1600 surely taking the wind from the X1650's sails) and i hope i can get my 3-screen-setup working with it.
what remains now is replacing the PSU, I'm ogling with a Be Quiet! one...
Cheers!