A massive Democratic wave in 2008 could spell the end of "Democrats need to do X in order to win" literature for the foreseeable future. The electoral difficulties that Democrats have had to live with for a few decades now would be over, and the first, solid, post-civil war "natural" Democratic majority without the remnants of the "solid south" would be achieved.
I think we've had a generation of a political-media-industrial class which has been completely infused with a narrative of Republicans are ascendant/Democrats are in decline. I'm not sure anything can dislodge this mindset.
I say political-media because it isn't just an issue with the media. Democrats and people who claim to speak for them are to blame for this is well. But I'm not optimistic that Democrats achieving a far greater advantage in Congress than Republicans ever managed to do would kill off this zombie narrative.
It's also clear that there are factions that are very wedded to the "what Democrats need to do" literature because they're interested not in simply winning elections but in remaking the Democratic party in their image. For some the 2006 election win was premature as the Democrats won without massively repositioning themselves, proving it was possible.