Okay, not one of the most well-known Xmas tunes, but I've known it for years, cos it's 
Home Alone 2, and it's great.

Anyway, a strum pattern like this works really well,

   D D U  D D U
e]---2-2----2-2-|
B]---3-3----3-3-|
G]---2------2-2-|
D]-0------------|
A]--------0-----|
E]--------------| etc


VERSE

[D]
The cold wind is blowin' and the streets are getting dark
[Bm]
I'm writing you a letter and I don't know where to start
[G]
The bells will be ringing Saint John the Divine
[A]
I get a little lonely every year around this time

[D]
The music plays all night in Little Italy
[Bm]
The lights will be going up on old Rockefella's tree
[G]
People window shopping on Fifth Avenue
[A]
All I want for Christmas is you


CHORUS

[D]
(Tell me) I've got to know
                       [Bm]
Where do lonely hearts go
        [G]               [A]           [D]
Because nobody ought to be all alone on Christmas


The verse and chorus sections are repeated before the interlude, which is...


INTERLUDE

[G]
I'm all grown up but I'm the same you'll see
[F#]
I'm writing this letter 'cause I still believe
[G]
Dear Santa I've been good this year
[A]
Can't you stay a little while with me right here


Sexy Sax solo over the verse, then back to the chorus.


Easy peasy eh?