My bias is for some logical (or even creative, but genuine) connection to the casino.

Just a few examples:
--if the International (pre-Las Vegas Hilton) hotel were still open, IT would be the perfect casino to issue chips in foreign languages, instead of the Four Queens.
--Fitzgeralds and O'Sheas are the casinos with a connection for issuing a St. Pat's Day chips
--Harrah's could have issued a "Harrah's 500" chip to commemorate the NASCAR event last weekend that was sponsored by them. (But enough already with all the Boyd properties' Petty chips!)
--just about any casino can justify a New Year's chip, with all the year end partying going on
--some of the holidays are overdone, but I would like to see a Bastille Day chip from Paris Hotel-Casino. The Las Vegas Club, with it's sports theme throughout, has more of a "claim" to issue SuperBowl or other sports chips, though we'll continue to see them from many casinos
--I like any casino building facade or sign on a chip, and would like to see more of these. (For some reason, you see more buildings & signs on tokens than chips. One of my all-time favorites is the Landmark with the building inlay!)
-- another favorite is the Tasmanian casino featuring 4 animals unique to Australia (koala, kangaroo, taz devil, taz tiger). But if a LV casino did the same series, it would lose it's meaning.

You get the idea...

So, in summary, I'm looking for some congruence between the chip and the casino or it's theme / name, etc. It's fine to do something different occasionally, like the crazy April Fools graphics, but personally I think some of the LE themes with little or no connection to the casino are superfluous and excessive.