Not quite true. We should be 54 - 56 after this election. Then the Dems who have to run in 2006 will be very careful how they operate.
Heh...2006...I tell you that is going to be a very interesting subject. Plenty of Democratic senators in that class are getting very long in the tooth, such as Ted Kennedy (who will be 74 in 2006), Paul Sarbanes (will be 73), Dianne Feinstein (73), Daniel Akaka (82), Robert Byrd (89), and Herb Kohl (71). Unfortunately all of them are in pretty safe states that can elect a Democrat, though we can be very competitive in Wisconsin if Kohl leaves and slightly in West Virginia if Byrd retires.
Aside from them, I think the best targets in 2006 will be Mark Dayton, Ben Nelson and Bill Nelson. Anyone else will depend on the candidate who runs against them.