Later in the game, when I have the tech to use these units, I will often use ICBMs as 'artillery' to clear a path for ground troops.

Example :

I am invading an enemy continent and my tanks/ modern armor have run into a 'knot' of enemy resistance. Usually a city that has 4 or 5 Mech Inf fortified or something similarly costly to beat down. In order to take such a city, I simply back my tanks away from the target and NUKE the defenders, then move right in. (and my tanks go rolling along).

I've seen many threads that basically say that other people NEVER use nukes under ANY circumstances. They refuse to use them because they are afraid of AI retaliation. I have never experienced retaliation from the AIs I've nuked. Not once. Ever. In hundreds of games. Does anybody else out there actually use ICBMs ?