That all seems to echo my own research today. I did eventually find a decent site with some explanation of the differences between the 754 and the 939.

I know it's proably foolish to plan on upgrading within the same CPU line, but last time I upgraded I went with the middle of the line (the 2100+), so I feel like I had less room to squeeze performance improvement from the same line. Looking back, if I had started out with a 1500+ and then upgraded to 3200+ later on, it would have been far more worth it.

No, I don't need a super fast PC, but I would like a decent amount of processing power. I won't be playing the latest games, but I will be doing quite a bit of video stuff, like capturing, editing, converting, and DVD creation. That all takes a lot of time. I'd like to shorten that time. So basically I'll be looking to get a better CPU, and go inexpensive on the video card side.