Mine seems to be updating too, though it's still a little flaky. The first stock I clicked on said "loading data" for the graph, then showed nothing. Changing the time frame got it to work, though.
I've noticed that though they look very similar, the widget on the iPhone is kind of better at this point, for instance now allowing reordering of the stocks (as of 1.1.1). It also uses Yahoo! Finance for the quotes instead of Quote.com, presumably thanks to Apple's deal with Yahoo! for push e-mail on the iPhone. I'm hoping Leopard will have an updated widget or Apple will provide an update for download.
Seen any good alternative widgets to try?