The best speaker you ever heard?

In my opinion, the speaker is by far the most important part of the audio system. After all, it is the only part you hear. OK, the other stuff really matters a lot, but without a great speaker... No go.

I am a bit 'speaker-obsessed' I guess, and now I am wondering: What are the best speakers you have ever heard, and what made them the best?
Duevel Jupiters... I love their smoothness, warmth and soundstage...
The Von Schwiekerts I heard were heavenly. If you are on a tight budget,the amp is the most important.
My friend just got a pair of SASS "prototype" speakers from a someone who sells on eBay. They are large bookshelf sized. The company reportedly makes speaker for large music halls. Amazing sound. Has anyone heard of this company?
Vintage SANSUI SP-5500's is one of the best AT ANY PRICE $$$$