A new list of the world's largest defense companies from the Stockholm
International Peace Research Institute:

http://www.sipri.org/contents/milap/milex/aprod/sipridata.html

The top 10:

1. Lockheed Martin (USA)
2. Boeing (USA)
3. Northrop Grumman (USA)
4. BAE Systems (UK)
5. Raytheon (USA)
6. General Dynamics (USA)
7. Thales (France)
8. EADS (W. Europe)
9. United Technologies (USA)
10. Finmeccanica (ITA)