Maybe I haven't run out of opponents, they have either died or left my area of "influence".
I enjoy the American Civil War, I personally favour the Confederates, but that's just me. The land battles are always covered with a lot of different games and miniature rules. The water or sea battles are something not often dealt with. I have a friend who I played Ironclads with on a semi regular basis when I was first made redundant (late 90's) but have since lost contact with him.
The game was excellent, but requires a little knowledge in the charts and tables. I always left that to my opponent, instead enjoying the havoc caused by the differing results of ammunition used. An excellent game, I highly recommend to anyone who enjoys this period.
The other genre of games I enjoyed the most was Air Force by Battleline. The Avalon Hill version is something that should be avoided at all costs. Too complicated. The game was introduced to me when I was at Griffith University doing my Science Degree. My dearest friend, now sadly departed to the next life, and I with a select few would play these games in the study cubicles at the University. We had a campaign system and pilot progression. An excellent game, sadly forgotten by many today.