I concur 100% with this. The 'main' reddit isn't all that great and more of a distraction than anything. The strong use of subreddits has increased my interest in Reddit strongly over the past few months. Otherwise yes, what is on the front page is just a precursor to what will be on Digg the next day.

That being said, these things just funnel around in a hierarchy. HN, Slashdot, Reddit, Digg, etc all suffer a bit from this.