I actually prefer wars in the modern age - as long as I have built the UN and have disabled nukes.
Without the temptation to "just nuke 'em" I am forced to engage in very entertaining conventional land wars. In fact, I prefer to take on the toughest enemy just so I have a good fight. There's nothing like the rush of stealth bombing the bejesus out of an unsuspecting enemy, then rolling him with modern armor. A strong AI's counter attack, with or without allies is fun because it makes the final turns of the game, with or without a space race, even more exciting.
On Noble/Archipelago/Epic/Chinese this is usually a rather challenging method of end-game strategy, since all the AI's that don't like you will join forces with a stonger enemy and attack you all at once. I usually play with lots of ocean squares, so transporting armies across large bodies of enemy-infested waters (especially with enemy subs around) is FUN!
-War, it's fantastic.