I remember when Tiger came out, and the widgets would take up about 20-30 megs of real memory each. If you had 512 or less memory, this tip was great to improve performance.
But recent updates to Tiger have seen new memory optimized widgets. I have a couple of widgets open (calculator, weather, dictionary, sticky, etc.) and all take up around 6-8 megs of real memory each). If you have a widget that's taking up 260 megs of real memory, it's time to get a new widget.