I think I've narrowed down the problem to the Adobe Flash Player extension. Not sure if it's the sites that are on my homepage(s) or sites that I go to on the regular, but I've slowly worked back to the extensions I've always used and the problem only comes back after installing the Flash Player.
It very well could be some random quirk of my system so I don't feel right saying that Adobe's player is the cause. But, without it, everything is working well. I'm gonna continue on for a bit without Flash to see if FF runs smoothly.
I really appreciate everyone's thoughts on this. But suffice it to say that I'm not addicted to a particular browser----if FF keeps messing me up (on its own or with the Flash Player extension) I'll use Opera all the time without batting an eye. If 0.6 works fine, I'll continue to use it. I just thought some others may have had a similar problem with 0.5.
Thanks again for the responses all. Community support is where it's at.

