After I upgraded using arjanv's 2.6 rpm's everything seems sweet.
I had a problem with my usb mouse not working, but solved that quickly, no threads or discussions seem to mention the ohci usb driver, I had to change my /etc/modprobe.conf to include the line
alias usb-controller ohci-hcd
ehci and uhci are always used in examples, so if your haveing troubles with usb stuff, maybe this is the fix for you.
My other problems include complaints about no mousedev or keybdev modules, but this is because of redhats modified rc.sysinit as far as I know, so I dont think its a real show stopper.
last on the list is loads of errors about hotplug not being able to find files, something is wrong with pci hotplugging etc, etc. I assume this is to do with the upgrade but I dont know what to change to fix it.
Still everything seems to be working ok, so maybe I needn't worry, any tips or ideas welcomed.