I apologize for my overlong hiatus. Thanksgiving and rearranging my schedule around a new job, plus reinstalling Windows and Ubuntu on the laptop I use at home interrupted my post-a-snowclone-on-Friday habit.
The origin of this snowclone is unknown. [Of course, I welcome any dates on this usage!]
“Whatever floats your boat” is commonly attested, with ~46,000 Google hits, and an entry in the Urban Dictionary, and several seem to have an obligatory “floats”, while the Y is quite flexible as gloat, ornaments, emf, cephalopod, rocketship.
X needs to be a verb, and Y is the item to be Xed, and there is usually some kind of whimsical relationship between X and Y, or the phrasing has an offbeat quality. X and Y may rhyme as in “floats your boat” or alliterate as in “fluffs your flannel”, or Y is not something that naturally follows X in reference to “you”, as in “tweaks your udders.” Thus, “whatever tickles your fancy” does not satisfy this snowclone’s requirements, even though it means the same thing–it is more of a cliche in its own right.
Some other examples found via snowclone.pl:
whatever roxxx your soxxx
whatever jiggles your jello
whatever bangs your shutters [as seen on “Unblogged Snowclones“]
whatever marinaras your molinaro
whatever tickles your tastebuds
whatever blows your hair back
The Snowclones Database 
So, what about “Whatever blows your hair back,” from Good Will Hunting?
I could see that one going either way–does it tickle your fancy or float your boat?
There is a strog tendency for X (or its infinitive, at least) to rime or have an alliterative quality with Y.
mentioned in the “Unblogged snowclones” list on Language Log (#3765)
I think my favorite version of this is “Whatever jacks your lumber.” While seemingly rude, it can still be passed off as a reference to forestry.
During the grunge heyday I liked, “Whatever fuzzes your flannel.”
Whatever blows your skirt up.
“whatever blows your skirt up”?
I love skrolnik’s “whatever jacks your lumber” — I’ve personally used “whatever pitches your tent” and “whatever tightens your trousers” with the same risque intent.
When the context involves more elevated spiritual matters, however, might I borrow from Emily Dickenson and suggest “Whatever winds your sundial”?
Whatever creases your trousers
Whatever flips your burger
Whatever makes your seatbelt click!
Related: That really Xs my Y, as in, “That really grinds my gears”, or “You know what really burns my toast? Sour milk!”.
Garrison Keillor’s got a song about this snowclone. Here are the lyrics to “Whatever Floats Your Boat”.
http://prairiehome.publicradio.org/programs/2009/10/03/scripts/boat.shtml