Surely, to be a 'great' general, the general should have been at general rank, and commanded troops on operations at that rank, in a war.
... but I'll throw General Anthony Zinni into the frying pan here - in my humble opinion a great general who may not have led CENTCOM in a 'war' (by traditional standards) but contained Saddam while picking up the diplomatic slack (in the Middle East) that the DoS could not or would not provide during his tenure.

Via Wikepedia, his career as a general officer:

His initial general officer assignment was as the Deputy Director of Operations at the U.S. European Command. In 1991, he served as the Chief of Staff and Deputy Commanding General of Combined Task Force Operation Provide Comfort during the Kurdish relief effort in Turkey and Iraq. He also served as the Military Coordinator for Operation Provide Hope, the relief effort for the former Soviet Union. In 1992-93, he served as the Director for Operations for the Unified Task Force Somalia for Operation Restore Hope. Also in 1993, he served as the Assistant to the U.S. Special Envoy to Somalia during Operation Continued Hope. Zinni was assigned as the Deputy Commanding General, U.S. Marine Corps Combat Development Command, Quantico, Virginia, from 1992 to 1994.

From 1994 to 1996, he served as the Commanding General, 1st Marine Expeditionary Force. During early 1995, Zinni served as Commander of the Combined Task Force for Operation United Shield, protecting the withdrawal of U.N. forces from Somalia.

From September 1996 until August 1997, Zinni served as the Deputy Commander in Chief, United States Central Command. His final tour was from August 1997 to September 2000 as the Commander in Chief, United States Central Command, MacDill Air Force Base, Florida. He organized Operation Desert Fox, a series of airstrikes against Iraq during December 1998, with the stated purpose of degrading Iraq's Weapons of Mass Destruction program.