I've tried some kernels, by typing it in the bootloader, but there didnt change a lot systemwise.
The Chocolate_kernel brought me back to 10.0.0, and the Legacy_kernel to 10.4.0, If I use lec_kernel (renamed it to that, easier to remember), which is the newest from Andy. I get the same results of the Legacy_kernel.

Though, the USB hardware still don't recognize any USB devices, except from my mouse. (Logitech G500) My keyboard is a PS/2 one (Also from Logitech).

Noticed something new though. When I plug my 4GB USB-Stick, nothing happends, ok.. Thats not new. Though If I replug it, no matter if it is in the same USB port or a differend one, the whole system stops responding. (Most likely a Kernel Panic.)Though I don't see any errors appearing.

edit: This is the kernel result right now (the newest one)
Darwin Richie-Holzkens-Mac-Pro.local 10.4.0 Darwin Kernel Version 10.4.0: Tue Jul 27 15:35:59 EDT 2010; annappirtrvh v4 :xnu-1504.7.4/BUILD/obj/RELEASE_I386 i386