It’s a lovely shot. I’ve been wanting an ND filter myself for those kinds of effects.
One thing to keep in mind about your aperture is that past a certain point you actually stop gaining additional sharpness and depth of field and start getting diffraction softening which can muddy your photograph. It might not be noticeable at small sizes (and I don’t see a problem with the above web-sized shot), but it’s something to keep in mind if you’re shooting something you want to print, particularly if you want to print larger sizes (8×10 and above). For an APS-C sized sensor, you start getting diffraction softening around f/11 or f/16, while with full frame you might be ok up to f/22, depending on the final print size. The reasons are complex, having to do with more math and physics than I can generally comprehend, but there’s a decent tutorial page here: