Zion's "hybrid edition" is known to be one of the better copies of the movie.
nfo file said:
This DVD is mainly a cleaned-up version of the original WBBM transfer,
taken from a 2nd-generation VHS copy. I added the commercials from the
WMAR version posted on Google Video in order to sync up with the RiffTrax
audio. This is far and away the best quality version of the Holiday
Special currently in circulation, IMHO.
I'd say I'm inclined to agree with him. You can find it over at the Spleen and it appears to be well-seeded.