some options:
you *can* put your CD music *on* your iPod by dragging the .aiff files into iPod that is connected by using the FW HD mode. however, these music won't be playable by iPod.
if you want to play raw CD format on your iPod, rip the CD as .aiff to iTunes first, then sync with iPod.
in summary, previous poster is correct, you cannot put music on your iPod that is playable by iPod without going through iTunes. (there might be some hacks. you might want to look around versiontracker.)