It was my original intention to have more Mexican War content on the blog, but I've never gotten around to it. This is just a short list of my favorites, and a few others from the 'to read' pile.
1. So Far from God: The U.S. War With Mexico, 1846-1848 by John S.D. Eisenhower. Jack Bauer's The Mexican War, 1846-1848 is another solid candidate for a standard midsized military overview.
2. Climax at Buena Vista: The Decisive Battle of the Mexican-American War by David Lavender. This a fairly dated account, but still a good single volume history of the U.S. army's northern campaign (Palo Alto, Monterrey, and Buena Vista).
3. On the Prairie of Palo Alto: Historical Archaeology of the U.S.-Mexican War Battlefield by Charles M. Haecker. New perspectives on the battle based on the modern field work.
4. The United States and Mexico at War: Nineteenth-Century Expansionism and Conflict by Donald S. Frazier. A nice, big, expensive, and out-of-print reference book that is worth getting if you can find it for a decent price.
5. Doniphan's Epic March: The 1st Missouri Volunteers in the Mexican War by John G. Dawson. Very good modern history of Doniphan's famous southwest expedition, with nice accounts of the battles of El Brazito and Sacramento.
6. California Conquered: The Annexation of a Mexican Province, 1846-1850 by Neal Harlow. This is the best scholarly account that I've come across.
7. A Gallant Little Army: The Mexico City Campaign by Timothy D. Johnson. Nothing better has been written about Scott's famous campaign.
8. History May Be Searched in Vain: A Military History of the Mormon Battalion by Sherman L. Fleek. The Norma Ricketts book The Mormon Battalion: U.S. Army of the West, 1846-1848 is another modern unit history, but with a more bottom up structure and mixed reviews.
9. Wars Within War: Mexican Guerrillas, Domestic Elites, And The United States Of America, 1846-1848 by Irving W. Levinson and 10. A Glorious Defeat: Mexico and Its War with the United States by Timothy J. Henderson. I haven't read either, but I thought I would include a couple decently regarded books that engage the Mexican perspective.