I usually prefer more realistic games, but for "beer and pretzel" wargames, the MB series is tough to beat. Axis and Allies has been revamped into two games for the Pacific and European theatres. Fun, but not as good as the original.
Samurai Swords is OK. Fortress America was one of the best balanced games I ever saw, but you had to have 4 cutthroat players to make it really work. Another great in that series is tough to find, but well worth it. Set in Ancient Rome "Conquest of the Empire" is well worth picking up on ebay.
"Europe Engulfed" is a step up from A&A, and uses wooden blocks (blank facing to opposite player) to create a good "fog of war" experience.
As for the civil war, I highly recommend "A House Divided". Counters instead of plastic pieces, but a great game!
http://www.alanemrich.com/Games_Arch...pages/ahd3.htm
Also, on the PC Sid Mier's "Gettysburg and Antietam" is a hell of a lot of fun.
If you want a great game set in the modern day, scrounge up a few others and a copy of "Supremacy". Think A&A+Diplomacy+Monopoly with Nukes!
I've been a game geek since Avalon Hill was new, and am always happy to help a fellow grognard. Have a good one.