According to the Daily Kos' weekly tracking poll
, only 23% of Republicans probably won't vote in the 2010 Congressional elections, while 40% of Democrats probably won't. To contrast, a whopping 81% of Republicans are planning on voting, while only 56% of Democrats are planning on voting.
It could be due to Democratic dissatisfaction with the current administration / Congress, or just a lul in political interest levels after Obamamania. Whatever the reasoning behind it, it's great news for Republicans.