Holiday movies like A Christmas Story, A Charlie Brown Christmas, Rudolph the Red-Nosed Reindeer, and generally all Christmas music never really get old.  That point can definitely be argued, but I consistently find myself getting exciting about watching these things and hearing these sounds year after year.  Is it because they're artistic masterpieces that deserve to be played non-stop for 30 days each year?  Probably not.  I think it's more about us as American consumers being cultured to get excited about a particular time of year.  Everything we see on TV, movies, and commercials gives the impression that Christmas is a magical time of year where dreams come true and hoofed animals fly.  Broken marriages are fixed, long-lost family members are reunited, and people get new cars.  Basically, everything is good, and even though we know it's not true and we get sick of hearing about it, the idea gets ingrained in our minds.  Eleven months go by, we see a commercial for some standard holiday TV specials, and we get excited again. 

Update (2006-12-19 11:08am):  The other thing I planned on saying was this:  Because of the excitement and fascination that goes along with holiday media, anything geared toward this topic will inevitably have tremendous success and become an instant classic.  The movie Elf is a good example.  The story is nothing spectacular and the characters aren't anything groundbreaking, but because it's a Christmas movie, it'll be bought and watched extensively during the Christmas season.  It's the same with any musician who makes a Christmas album.  That artist is pretty much guaranteed a major sales increase every year.  And because there's never really any "new" Christmas music (just redone old Christmas music), the songs and albums will never really get old.  They're instant "timeless" classics.  What a concept.