I don't think you can copy a bootable OS X partition as simply as that, but OS 9 you can, so long as you "bless" the System Folder.
However, for OS X, you only need to copy the following directories, after doing a clean install of OS X:
/Users (all your home directories)
/Library (all your universal preferences, fonts, etc)
/Applications/<non-default-apps> (copy only the applications not installed by default)
Unless you've done some non-standard OS X stuff, this should be all you need to get your OS X system on the new machine looking like the old one.