Nicest of the Damned
It seems like the aggregator could be reduced to a panel (like the Mozilla sidebar, or perhaps a floating palette) so that you could watch the headlines come in without leaving the browser, and your browser could better manage the resulting windows.
Frank raises the question of how long aggregators will exist outside the browser, instead of being another module or sidebar panel. I think it makes some sense, but I wonder if a fatter aggregator that could display pages in some form would be better than an even fatter browser.