roguetiger wrote:
I went with the Phantom X-19 and only one I see

.
You have some company now.
Phantom X-19 gets my vote too, even though I was only able to obtain one as an adult. A futuristic design that is both beautiful and semi-believable (except for the overly forward cockpit). It even looks like the aircraft used in the movie Stealth (though that might not be the greatest movie to be associated with).
I've always wanted a Rolling Thunder, but as Pluv pointed out, it's a Jack-of-many-trades but master of none. I think the ICBM missles are cool, but doesn't make a whole ot of sense for GI Joe who are supposed to be defending the world against Cobra, not launching ballistic missiles at other countries. Come to think of it, this would have been an awesome Cobra vehicle.
The Warthog APV was one of my most used vehicles in the day, as it made a fantastic personell carrier. However, I've always disliked those large orange torpedo/missles on the top. If it had come with a rack launcher like the Wolverine or a chain gun, it could have easily been the #1 vehicle of this year for me.
My brother had the Swampmasher, and I must say this vehicle was the best and worst of GI Joe in one vehicle. Best because it had an awesome minigun, well detailed engine, cool futuristic triple wheel design, and nice buggy design. Worst because the colors totally ruined this vehicle and negated all the positives I just mentioned.
As Rougetiger mentioned, I also remember reading the Popular Mechanics article about the vehicle similar to the Skystorm Chopper, however as mentioned the toy fell far short of the real thing. The fact that Windmill was one of the lamer vehicle drivers out there didn't help.
It surprised me to see how many Desert Fox fans are out there; I never liked this vehicle and didn't know anybody else (until now) who did. It just didn't have "the look". Skidmark' is a great figure mold cursed with a terrible headsculpt and nickname.
Everything Kingofpain said about Mean Dog applies to me as well; I thought this was a garbage vehicle until I finally got one. It doesn't work well for me seperated into smaller vehicles, but like the Maggot, as a whole it is a pretty cool vehicle to bulk up the Joe fleet.
To me the RPV was and is a junk vehicle, although in reality the use of unmanned vehicles has become a staple of the armed forces.
Surprisingly, after such a poor year in 1987, this year turned out to be a pretty good year for Joe vehicles.