Mine is "Sherlock Holmes : The Hound of the Baskervilles".
[From Frogwares.]

It's never lost its appeal

I don't replay games, but I play Fairway Blast every day. I can play solitaire anyday!

My most replayed casual game is Caribbean Hideaway, a match 3 game. I've probably played and finished that about seven times. I've also played some of the Delicious: Emily games three or four times.

And I have played Hound of the Baskervilles more than once.

Oh, I play Jewel Match Twilight every day

But The Hound of the Baskervilles is my most replayed "story" type game

I play BVS Solitaire everyday. I don't replay other games.