Have American forces been strengthened or broken by the War on Terror campaigns?
The Small Wars Journal summarizes a Center for a New American Security and Foreign Policy survey of more than active service and retired 3,000 officers with the rank of major and above across the services, 2/3 of whom had combat experience. According to the survey's website "The nonscientific survey was administered online from December 7, 2007, to January 15, 2008."
Interestingly the biggest identified constraint in prosecuting the War on Terror isn't the size of the Armed Forces, though that is certainly one of the respondent's top priorities. It's getting good intelligence, a desire supported by the sizeable number of respondents who thought it was a good idea to "increase the number of troops with foreign language skills."
Perhaps the most significant piece of long-term strategic data was where the respondents thought the increase in strength was going to come from. From the response they had all but counted out expecting reinforcements from the national elites.