I was never a fan of Twin Peaks, but it had a lot of critical acclaim and a lot of talent behind it -- it was created and produced by David Lynch. So although you may not have heard of it, it did have a fairly big impact in its time. It only ran two seasons but interestingly, it started the same year as Seinfeld.
That said, Seinfeld has much, much broader appeal. As the #1 TV series of all time by some surveys, it's virtually guaranteed that all Seinfeld seasons will come out on DVD.