After each Apple event, we at MacRumors like to recap the winners/losers of the rumors circles to find out who had the scoop...
No new PowerMacs... Despite early rumors and expectations of PowerMacs at MacWorld... CNet and ThinkSecret accurately predicted that no PowerMacs would be on their way. As far as rumor reliability goes, CNet historically has been very accurate when they do publish rumors. (CNet had also reported that Jaguar would be available in August)
ThinkSecret also accurately predicted the 20GB iPod and iTunes update.
PC iPod... The PC iPod rumors originated back in April, and resurfaced in June at MacMinute.
Added: Spymac predicted iTools Pro back in April
Not Quite Yet or Not Quite Accurate... 1.5Ghz at MW?, Laptop Revisions?, MultiButton Mouse?, New PowerMacs at MWNY.
Rumors to keep an eye out for...