My top 3
3. Miracle on Evergreen Terrace - The Simpsons - the one Bart burns the tree down and claims it was a thief. Love the scene where Marge is on Jeopardy, finishes on -$4800 and is asked by Alex Trebek to pay up. Always a running joke in our house if anyone finishes the show in the red these days

2. Christmas - Married...with Children - when Al is forced to work as a Santa in the mall to get enough money to buy the family presents (then steals them all from the bar anyway). Love the scene where Marcy is on Santa's/Al's lap, and Jefferson is going down the line-up for Santa mistaking every little boy for Marcy before Marcy gets the kids to sing 'Bundy the No Man' (to the tune of 'Frosty the Snowman).
1. A Very Special Family Guy Freakin' Christmas - Family Guy - where Lois has a nervous breakdown on Christmas Eve. The end of the episode always has me in stitches!