The new Google Finance service is really slick, a much better layout than Yahoo! Finance and some nice extras like charts that are draggable and have links on the tick marks to major news stories. Also worth noting is that they are linking blog posts about the stock in question to the finance page (would love to see the criteria and filter for that). SeekingAlpha has a much better post than mine on what the service is offering and why it's significant.
Google Finance: Oracle Corporation (guess their earnings announcement yesterday was a little disappointing)
UPDATE: For some inexplicable, this link to a post explaining how Google Finance is an example of how Google is no longer an innovative company was in a comment to an unrelated post.
UPDATE2: Interesting to see the debate about this, Om thinks it's a disappointment while Charlene thinks it's a strong offering. The reason why I think it's a good service is that it gives me more of what I need right up on the front page, there's less clutter than on Yahoo!'s finance page. To put it another way, I don't think that what Google has done here raises the bar to a level that is beyond the immediate reach of Yahoo!, quite the opposite in fact.