Interesting, I was just reading Sviatoslav Richter's "notebooks and conversations" in which he says of the classical composers, he liked Haydn the best.
As to memorability, clearly the great string quartets are memorable as well as some of the London symphonies. His sonatas for solo piano (see Richter comment) and his luminous trios for cello, piano, and flute are all greatly memorable pieces too in my opinion. That's a fairly large body of works to have labled as "competent but not especially memorable" IMHO.
p.s. Richter's book is an easy and worthy read--mostly biographical with lots of opinions on many topics, especially modern composers and musicians he played with.