Hate to be a buzzkill, but read Ron Brownstein on the difficulties of racking up huge midterm election gains. I fear some serious lowering of expectations here, as Democrats talk up their chances of gains ("Three chambers of Congress! The House, the Senate, and one Rahm Emanuel HASN'T EVEN INVENTED YET!") and the Republicans inflate their likelihood for loss. If this gets bad enough, I fear anything less than a a total, crushing victory, particularly in the House, will be seen as a "win" for Republicans.
Meanwhile, I'm fairly convinced that Dems would be better off radically shaving GOP margins in 2006 but not actually capturing Congress. Creating a 50-50 split in the Senate and a closer margin in the House would allow Democrats to be effective in the opposition without getting tied to the continuing implosion of the GOP's policy agenda. That's not to say it's my favored outcome, but it seems the most politically advantageous (or am I just lowering expectations myself?).