He was also brilliant in One Flew Over The Cuckoo's Nest. Mind you everyone in that film was brilliant. The guy that played the mad professor in Back To The Future was in Taxi as well. Christopher something I think. He was hilarious as well.
Jack Lemmon is a star. One of my all time favourites. "Days of Wine and Roses" http://www.imdb.com/title/tt0055895/?ref_=nv_sr_1 Made in '62 it's an excellent morality/warning on alcoholism.