In continuing the lame attempts to get some more action in this board...

Season 1:
BEST: "The One With All the Poker"
WORST: "The One With the Thumb"

Season 2:
BEST: "The One With the Prom Video"
WORST: "The One With Russ"

Season 3:
BEST: "The One Where No One's Ready"
WORST: "The One With the Ultimate Fighting Champion"

Season 4:
BEST: "The One With the Embryos"
WORST: "The One With the Cat"

Season 5:
BEST: "The One Where Everybody Finds Out"
WORST: "The One With Joey's Bag"

Season 6:
BEST: "The One On the Last Night"
WORST: "The One With Mac and C.H.E.E.S.E."

Season 7:
BEST: "The One With Monica's Thunder"
WORST: "The One With the Vows"

Season 8:
BEST: "The One With the Videotape"
WORST: "The One With Joey's Interview"

Season 9:
BEST: "The One With Rachel's Other Sister"
WORST: "The One Where No One Proposes"

Season 10:
BEST: "The One Where the Stripper Cries"
WORST: "The One Where Joey Speaks French" (this may be the worst episode ever)

Finding a worst was harder than I thought. There's something I love about every episode.