One feature of Activity Monitor.app I didn’t notice before (nor have I seen it referred to on the web) is that it will tell you whether any running process is PowerPC or Intel native. The column is enabled by default on Intel Macs (but you might have to scroll to the right to see it :) It’s disabled by default on PowerPC Macs, because, uh, what’s the point?
This makes it pretty easy to weed out those non Universal Binaries lurking on your system. It seems that I only run 1 or 2 regularly on this machine, and they should be “native” before long. My dual G5 will still be doing the heavy-duty apps (audio, video) for the time being…