List of vulnerable Democrats in 2010:
1. Chris Dodd in Connecticut
2. The Obama seat in Illinois
3. Harry Reid in Nevada
4. Arlen Specter in Pennsylvania
5. The Biden seat in Delaware
6. Blanche Lincoln in Arkansas
7. The Salazar seat in Colorado
8. Byron Dorgan in North Dakota
9. Scores of House seats
This is a partial list compiled by Time Magazine before the effect of the Kennedy Senate seat loss in Massachusetts had a chance to set in.
Link