Ok, so I was a bit spontaneous. I should never hastily rush and install a new Operating System the day of it's release. Nope, nothing is wrong, well at least with my installation! But i'm hearing reports of bad installs (blue screens of death) and other reports of odd things, like the latest version of Java not being supported on Leopard. Hmm. Hopefully those can quickly be resolved, and luckily I didn't encounter the blue screen and I'm not a Java developer (though I aspire to be one day!)
So, I'm fortunate - no hassles and an awesome OS, pity that these things are marring what would otherwise be a most excellent upgrade. I guess the pressure of a set deadline gets to everyone, even Apple.