I have to go with the civil war. It's very well documented, the personalities are wonderful, and I think the build-up to the war and the early months illustrate the dangers of not taking war seriously. It's also interesting to watch how tactics, strategy, organization, and supply evolve throughout the war. Plus Sherman is one bad muther hubbard.
personally ww1, the pacifc in ww2, and the colonial wars that the british fought. also the apache wars.
i like ww1 and the pacific mainly because of realitives that served. after reading diarys and officer reports of some of the battles, those guys survived thru some things that after reading you think how the hell could they take that sort of punishment and continue on, they have my utmost respect and always will.
also the lighthorse in ww1 who did a lot of work where there weren,t any trenches.
For some reason I'd also go with WW2. Somehow it intrigues me. My fave movies are Patton, Longest Day, etc. My term paper in high school was about D-Day. As a senior and to this day I could list you the 5 japanese aircraft carriers that attacked Pearl Harbor. I dunno why but when other kids in school were reading "Joe Schmo Music Book" I was into the books about WW2. They had a time life set of the color of war. Im very strategy based so maybe Im Patton reincarnated and taking a break lol
Other wars are just there but its wierd how I have been a WW2 buff for about 15 years and am still learning new things about it all. Anyway, this is mine.