Thank goodness.
It turns out that the reason why my MacBook Pro was going insane was a certain rogue 1 GB stick of RAM. This explains a couple of things: why iPhoto was loading in the wrong thumbnails, why Activity Monitor and iStat nano were both reporting heavy memory usage, why everything was beachballing like crazy…
I’m just thankful that I’m back to a working happy computer. I just hope that there will be no more hiccups. Currently, my iTunes is complaining that there isn’t enough memory to open up iTunes, but that’s happened before. Time to continue! Lots of work to be done!