There should be a lot of close races, but it will depend a lot on the national climate.
Everyone seems to think that Webb, McCaskill and Bill Nelson are weak, I think they're all in an ok position.
Exactly. Unlike Republicans this year, Schumer picked great candidates in 2006. Brown, Webb, McCaskil and Tester are much better politicians and campaigners than Paul, Johnson and Coats.
I don't think those three will be running in OH, VA, MO, MT. Webb, Brown, and Nelson of Florida are in in ok position but not perfect or safe.
McCaskil's numbers are horrible and I don't think she will be able to do as well in central MO as she did in 2006. Tester's future depends on the environment and his opponent. If it's Rehberg, he probably has a real race and if obama gets trounced in MT, probably an uphill climb. Ben Nelson is in big trouble in Nebraska.
Brown and Webb certainly have some talent, that won't prevent them from being targetted though.