I've always been a fan of Seinfeld and knew who David was before his HBO show. After watching a coupon of seasons from Netflix, it really became clear who was the driving force behind Seinfeld. Jerry is a good front-man and has a great delivery, but the sheer lunatic genius is pure David.
Even today, 10 years or so since it went off the air, there are funny shows which use subtle, yet derivative, plots and other hints that point back to what were purely unique & singular comedic events.
Rumor has it that the character of Suzie on Curb Your Enthusiasm is based on Laurie David.