PPC fans rejoice, it looks as if the 10.6 System will still be Universal. Perhaps in the end, the 10.6 disc will contain universal code, but the OS Installer will only install binaries for a specific platform (detected at startup). It would be cool if Apple could do this, as Microsoft's solution for 64bit-ness has been a completely separate build on a different disc.
The problem with a 64bit OS, however, is that only 64bit kernel drivers will work. Thus, hardware support will be extremely limited, just as it is on Windows NT6 64bit. Since everyone is going 64bit nuts, I guess I need more RAM for my MBP--you need at least 4GB to run a 64bit kernel, so 2GB just ain't cutting it anymore.