From the National Journal's Chuck Todd
A few early observations:
Campaigns matter. The incumbents who have gone down are ones who two months ago didn't know they had a race on their hands (including Reps. Anne Northup of Kentucky and Charlie Bass of New Hampshire). Meanwhile, so far, it appears that the House GOP incumbents who were prepared are surviving this Democratic wave at a greater clip than some analysts anticipated.
Also, while it's still early and we're counting mostly votes east of the Mississippi, there seems to be a trend that GOP turnout is steady - not down, as some anticipated. The increased turnout of Democrats and independents will make the difference for many successful House and Senate candidates, but the non-disastrous GOP turnout should save the party some House seats. Case in point: Kentucky 04, where GOP incumbent Geoff Davis survived in a very conservative district.