Hearts of Iron 2, DD Arma is the bomb

I've been playing this for several years now.  I get tired of it sometimes, but then come back, maybe install a few new mods and it's like falling in love over and over.  Never got my money's worth out of any game as much as I have this one. 

The learning curve is a bit steep, and it's probably only appropriate for strategy freaks, history buffs and war mongers (if you like(d) Avalon Hill's games, you'll dig HOI2, plus there's no long assed rule book to memorize).