QUOTE(maggiemay @ Nov 9 2009, 12:46 PM)

I find it can be quite tricky to buy a book which fits any one particular level - especially as those who are keen to play carols are often not much more than beginners.
I often download the carol arrangements from
http://www.gmajormusictheory.org/Freebies/freebies.html these have proved popular and moderately successful in the past. Of course a book is nicer - and the only way really if you want to give something as a present. But for general 'oh let's play a carol or two' the downloads are not bad.
I agree - the download ones fit the bill very well (and there are a couple of other very similar sites).
If not, Hal Leonard's ones are graded, nicely arranged and not just carols (level 3 also has Rockin' around the Christmas tree and My Favourite Things if I remember rightly). Bastien proves popular too - yes, a bit old-fashioned in terms of arrangement but then, they're carols !
Have several books of 'jazzy' carols - no one likes them.
But downloads are great - cheap, cheerful, no trouble finding a pupil's particular favourite - I give them out one a week as sight-reading/prepare yourself practise too.