Third party RAM could be a possibility as it gives up very quick. Not long after the Happy Mac there's no more disc activity from the cdrom and then after a minute or so it panics. I might just give it another shot with the extra 512MB module out but chances are the iMac is just too new.

I went ahead and installed 10.0 anyway and damn it's scary how basic it was (I started my OS X days with 10.2.1). Even the beta had a Music Player but in 10.0 putting in an audio CD gets you a Finder window of the aiff files. DMGs won't mount in Disk Copy. System Profiler looks just like the classic one in an Aqua skin. Talk about humble beginnings