Ignore Max Hastings is step one. Bad detail, usual bias, generalizations that aren't true, and the same old insignificant anecdotes which are just there to make the story seem compelling but are usually tangentially related.
Good general history: John Toland. His WW2 books are a real example of nuance, objectivity, and skilled writing. Same thing here.
Best general history (if you can find it):
http://www.amazon.com/The-Korean-War-Volume-1/dp/0803277946
Three volumes, loads of information, and plenty of vignettes which demonstrate what the combat was actually like and what the stakes were. Also, unlike almost everything else you'll read, this doesn't leave the Koreans as a footnote in a war between the US and China. The RoK is center stage here and it actually explains what the KPA was up to after we shattered it. (they regrouped and mostly fought Gainst RoKs and army units in the more mountainous regions of the front line) There were more battles than you'd realize if you rely on books like those from someone like Max Hastings.
The last of those is actually the ROK army's official history. I'd say the best general history is Allan R. Millett's trilogy, including The War for Korea, 1950-1951: They Came from the North (Univ Press of Kansas, Modern War Studies) 2010
The US Army also has an official history, but only a couple volumes. Roy Appleman, who wrote at least one of those, then did several volumes on US Army ops that are pretty good (and more stimulating reading than the Greenbooks). There is a volume in the Leavenworth Series from the Combat Studies Institute titled Counterattack on the Naktong, plus an essay on artillery, etc. See
http://usacac.army.mil/organizations/cace/csi/pubs for downloads. (Most Center of Military History pubs can also be downloaded as PDFs if you go to their site, including many if not all the Greenbooks and probably including the KW volumes.)
See also Kenneth W. Estes, Into the Breach at Pusan: The 1st Provisional Marine Brigade in the Korean War (Uof Oklahoma Press, Campaigns and Commanders Series) 2012. If you're willing to get a bit less tactial, and a bit more academic, there are a number of recent works on the Chinese side:
Mao's Military Romanticism: China and the Korean War, 1950-1953 (Univ Press of Kansas, Modern War Studies)Nov 28, 1995
by Shu Guang Zhang
Mao's Generals Remember Korea (Univ Press of Kansas) 2001
by Xiaobing Li, Allan R. Millett and Bin Yu
China's Battle for Korea: The 1951 Spring Offensive (Indiana Univ Press, Twentieth-Century Battles) 2014
by Xiaobing Li
And for you Commonwealth men, The Imjin and Kapyong Battles, Korea, 1951 (Indiana Univ Press, Twentieth-Century Battles) 2013.
by Paul MacKenzie