Some thoughts:
Deleware- Depends on whether or not Castle runs. A close election, though
Unless Castle runs, Republicans are fu**ed there
Nevada- Republicans will pull it together and nominate someone to defeat the unpopular Reid
North Dakota- Hoeven will end up running, and the results will be similar to SD in `04
Yep, but I'll believe in Dorgan narrow victory
Arkanas- Could potentially become competitive, if the Republicans find a good candidate
I can't see a candidate now
Illinois- Polls will show this close for a while, but it will come home to the Democrats in the end
New York- Pataki could beat Gillibrand, he really could. That will be a fun race to watch
Gillibrand was Patterson biggest stupidity
Pennyslvania- There will be a bitter Democratic primary, but in the end, Specter will go on to barely defeat Toomey, in another close race.
Toomey would not come close to either Specter or Sestak
Overall, Democrats really lucked out that they don't have as many seats to defend as the Republicans. If Senate elections were every 4 years instead of 2, and the `06 class was up for re-election, Republicans would probably come close to taking a majority in the Senate.