Lifts I will be sad to see go:
Segundo at Sunlight.
Towers were first installed at Aspen as the original chair 3 (now Ajax Express two lifts later). Installed at Sunlight in 1973. At Aspen the chairlift was a single. Riblet came in and re-engineered the lift to be a double, installing classic Riblet double carriers and top and bottom terminals. Lift is a vault drive from the top terminal. If you say this lift is a 1955 lift it is the oldest operating chairlift in Colorado. If you date it to 1973, it is still one of the oldest. It is a testament to quality that most of the oldest lift still spinning in Colorado are Riblets (Monarch's 1960's Halls got new drive terminals the past few years).
Chapman Hill
Still operates with two rope tows. One of them was first installed at Camp Hale on the "B Slope."
Ski Hesperus
Riblet double of 1960's ish vintage. Transplanted from Mt Bachelor. Barely hanging on, both as a ski area and a lift- there were metallurgical concerns back in the 1980's. During the week, the ski area only opens at 4:00 for night skiing. Powder skiing under the lights (or lack of them) is epic.
Sipapu's Poma
Throwback in so many ways. Very old school detachable poma. Doesn't even have an electrical tap- they run a gas generator to provide power to the lift.
Wolf Creek Kelly Boyce Poma
Unfortunately has not operated since the 2012-2013 season. They used to spin the lift on Peak days to help with capacity with the old Treasure triple that runs parallel. However, since treasure was replaced with a HSQ (and the old lift reinstalled as Elma) they have not spun the Poma.
The Poma is one of the wildest rides I've ever had on a surface lift. It runs up two faces that run up to about 40*- one is pictured above, the other is just about the bottom terminal. Transitioning onto and off of the steep pitches tends to pull you off your skis- helped by the worn out springs in the carriers. To make things more interesting, because the Poma operates only occasionally and on pitches too steep to groom, you are commonly pulled up through mogul fields. If you see this lift spinning, ride it.
Merging some conversations, given that Wolf doesn't seem interested in operating the lift in its current installation any more, I would love for Wolf to refurbish this lift and install it either as the Meadows lift (see Ruining Wolf Creek thread) or running from the saddle on knife ridge up to Horseshoe bowl (replacing cat service there). Doesn't seem like there is any thoughts to doing so.