on par with the 1994 Republican Revolution.

Not exactly. While both houses changed, the 1994 Republican Revolution was a much larger landslide, where Republicans made a net gain of 54 seats in the House and picked up 8 in the Senate, causing several Democrats over the next year or so to change parties (ie, Ben Nighthorse Campbell and Richard Shelby). Their majority in both houses was twice the majority or more of what the Democrats currently hold, and was won on a platform of running as conservatives, rather than running liberal Republicans and former Democrats (which, in reverse, was largely the strategy of the Democrats in this round).

So, the Democrat win here was a big thing, but it's not proportional to the siesmic shift of 1994, which is a truly unusual event in American history. 2006 was more like what normally happens when the Congress changes hands (a slow loss of power over time, without large ideological shifts). American politics, overall, while more conservative than Europe's, tend to be confined to a much narrower band. Or, you could say, the US is much more stable and predictable than any other democratic power.