A speaker with a really deep bass, then look no further than a B&W 801 Nautilus. I have had the B&W Matrix, Series 3 and 801 Nautilus. Matrix 801 had pretty good bass with a 12-inch driver, but the 801 Nautilus was really something else with a 15-inch driver. The 801 Nautilus' bass was incredible and amazing. The bass strings on jazz recording really come alive...
I have auditioned Wilson Watt Puppies many times. They have pretty good bass, but not as powerful as the B&W Nautilus 801. Now if you are looking more for quick dynamics and transparency, Wilsons are hard to beat.
I have since moved on to Avalon speakers, but still miss the bass on the 801 Nautilus I used to have, and not by a little but by a lot!!!