2-way speaker with best bass

You did not mention any restrictions on speaker size so I am going to suggest the Emerald Physics CS-2's. They are a floor standing 2 way with an active digital crossover and require biamping. They are rated to 20 hz on the bottom end and the bass has outstanding pitch and extension. (2) 15 inch bass drivers in an open baffle design per speaker so they can really move some air. They do require significant driver break in time when new, particularly the tweeter. They also need to be at least 3 feet into the room as per the manufacturers set up instructions.

Dunno if it is the absolute best bass, but I bought a pair of Model 19s recently, had to re-solder some of the wiring to the crossover, finally got that done today and WOW! "BIG" sound at a great price. I have not found something else I would prefer at the price point.

That's right . . . "2-way" doesn't have to mean "bookshelf". Try a pair of JBL 4435s.

You want "tight and tuneful bass" in a two-way?? Check out Duke's Audiokinesis speakers. I have the Jazz modules and was amazed by the impact and musicality of bass produced by these speakers, which use a TAD prosound 10" driver. These are not small speakers, but they will work in small rooms (mine is 12x14) as well as large. The bass can be tuned using an adjustable port. I tried the Usher Be-718s in my room and enjoyed them, but really love the Duke's Jazz Modules. I'm finally simply enjoying the music and will not be looking to upgrade for a long time.

Of the speakers I heard at RMAF, Duke's Audiokinesis speakers were among the 3-4 that most interested me (I don't think the Jazz Modules were there), if I were actually looking to replace mine, which fortunately, I'm not. They certainly would match up very well with my Atma-spehere amps.