There are so many good ones, and I've yet to read them all, but a few are outstanding: CAMALOT, AKA911, IXXI. The binary ones are interesting, and I'm astonished that TARGASM was ok'd.
I2XLR8's owner might've applied for IXLR8, but that one's been in use in at least one state. Decades ago a car magazine had a picture of a Miura, I think, with it.
PANACHE reminds me that I considered a vanity plate for my new Boxster, but decided to stay with the standard issue. Last I checked, it's available in New York State: LAUDACE. (Imagine an apostrophe after the L.)