In the department I belong, we have a 29 year old American LaFrance Ladder Truck. You would never know that by looking at it, and it is still in great machanical shape as well.
In our station, our oldest truck is a 1984 tender w/1800 gal tank and (I think) 1,000 GPM pump. Our main station has a 1963 International that is their field fire truck and a 1982 Alexis Ford F-8000 that is the third due truck.
Youngest truck is the set of 2000 Alexis engines (one at our station, one at the main).
We just got rid of our 1988 Mack Pumper. It really wasn't too old, but that thing was unreal. I'll tell you though... it may have had some age, but you could drive that thing without an oil pan for 12 miles and it would just keep going. It shifted pretty bad, but it took a licking and kept on ticking! The pump pushed 1000 GMP at the tip of a smoothbore deck gun and she still had some fight in her. They don't build them like that any more.
1967 HOWE that is used as our rescue , trust me you don't wanna roll that truck top speed is like 37mph, but can't get the cheif to listen he wants to spec out another engine which we don't need.
1985 mazda pumper. Great as a stationary pump but takes a while to get to the fire and drives down hill with a tail wind like nothing else. They keep saying we are getting a new 1 every year for the past 5 or 6 years but we wont believe it till we have it sitting in our engine bay with our name on the side. Will be sad to see the old truck go there are many great memorys and fires from that truck.