There's New Found Glory's Ex-Miss and their cover of The Christmas Song. Personally, I don't think you can go far wrong if you listen to Weird Al's The Night Santa Went Crazy. Although, there's always the need to mention the Punchline Christmas Rap... [youtube]azWv-c05PQY[/youtube]
http://www.myspace.com/wordsfromreuben Reuben have uploaded a song called Christmas Is Awesome on their Myspace.
That reminds me of Panic! at the Disco's version of "This Is Halloween." That's got to be at the tops of my list, too.