Charlie Cook has some interesting things to say about the eight Senate races he sees as too close to call at this juncture. It's a very goos article to read to get caught up to date on this year's most important races. His conclusion, after detailing each contest:

First, Democrats deserve credit for keeping their Southern seats in play. The South is fairly hostile territory for the party, especially in presidential years, and very early predictions ran heavily against Democrats being able to hold even a couple of these seats. Yet Democrats recruited the kind of moderate candidates who can win in such an environment. Today, only their open seat in Georgia is a lost cause.

Still, winning control of the Senate is a tall, but not completely impossible, order. To win a majority, Democrats would need to win six of the eight seats if Kerry is elected, thus allowing Sen. John Edwards to cast tie-breaking votes. If the president is re-elected, Democrats would need to win seven of the eight seats. In short, Democrats have about a 30 percent of gaining a majority in November.

Link.