I am always perplexed when I hear the term grail and having it associated with a single watch, as others have said.
But, the two genuines I aspire to own, once I get back on my feet financially and get my daughter through schooling and into adulthood, would be:
JLC Master Compressor Memovox - I have the rep which is good but having the real deal with a working alarm would be better.
OMEGA 1960's Cal 322 Speedmaster Moonie
and
My birth watch is a 1960 Gilt Dial Rolex 5512
item of interest is the new PAM 372