The Choral Fantasy Op 80 (for piano, orchestra and chorus).
A self-contained 20 minute concert piece that is just sheer delight from beginning to end - and full of absolutely characteristic touches.
This is the version I got in 1977, on a Classics for Pleasure (bargain price) LP, by one of my very favourite Beethoven pianists: John Lill.
Lill gave one of the most memorable concerts I ever attended - a lecture-recital at the non-mainstream venue of Ashington Technical College. The highlight was when he played a Liszt Transcendental study. To see this performed close-up, and done by probably the premier British pianist of that time - and a player of unsurpassed power (a big man - domed head, broad shoulders, meaty hands - looming over the keyboard) - was something thrilling. I thought the instrument was going to collapse at several points! - but the execution was always lyrical and (apparently) technically flawless.