I was going to make some sarcastic and cutting remark about how people will go on about a "great old Schwartzkopf" or something, getting all misty eyed about some old POS like Thunderlooper or The Beast - how it's such a shame Anton's best old machines have all gone out to pasture and whatever.
Then I had a good long think about it, and the only ride I can think of that's no longer "available to ride" that I'd love to ride again is... The Bullet from Flamingoland. I was gutted when I realised that - bad_furie.
I'll second the Schwartzkopf love - while Dorney Park's Laser lives on in Mexico, it is defunct to the point that I'll never ride it again. It was my first Schwartzkopf looper, and quite a good one at that. Definitely makes you come to appreciate the awe of the Schwartzkopf loop!
I was actually going to put Flamingoland's Bullet as well. It was excellent, but the shoulder restraints could be quite painful. They had a horrible habit of sometimes tightening through the ride, leaving you in agony and unable to move until they were released.
Riding it as a lapbar only ride solved the problem fortunately.