Just a tip folks....
My experience with OS X has been fantastic. I've always updated through the software update control panel and never experienced any problem of any consequence.
Then, spontaneously last week, my machine began locking up. I'd get the spinning beachball of death and the only way out was to shut down. This frequently happened after clicking on a folder in the Finder, but it was never the same folder or even volume.
I ran fsck a thousand times, but nothing changed.
Finally, I happened to be looking under my desk at the time the beach ball came up, and I noticed strange light on my firewire hard disk. It was not the normal green flashing when it was being accessed, but rather, alternating between green and red.
Note that this drive has been working flawlessly for a year and a half.
As soon as I disconnected the Firewire HD, the beach ball stopped and my computer went back to normal. I plugged it back in for a day or two, and noticed that not only were the beach balls appearing, but at times it was starting to spontaneously dismount.
So, I got it to work long enough to copy the data off and reformatted it. No change.
Finally, I ordered a new Firewire HD enclosure from WeibeTech. Since installing that, everything is working perfectly again. So, it would appear something got damaged in the firewire circuitry of the old enclosure, and that's what was giving the OS fits.
The moral of this story? I was extremely frustrated and ready to blame the OS for acting flaky - but it turned out to be a routine hardware problem that was certainly no fault of the OS.
Wade