If you want to see and hear massive chunks of glacier ice crash into the water, this is the place. As you enter the bay you will note a total of seven glaciers clinging to the high cliffs on each side. Of these seven two still touch the water and drop massive quantities of glacial ice into the bay. Of these two, the huge Blackstone Glacier (for which, obviously, the bay is named) is the most impressive. At least two miles across and set in a very scenic position at the end of the bay a view of it alone is definitely worth the trip.
Most kayakers, myself included, enjoy staying out at a safe distance from the glacier and waiting for the rumble of a calving glacier followed by the huge splash and big wave to follow. The water here seems to be normally quite calm and though there are bergy bits and icebergs aplenty, it really isn't overly dangerous as there are lots of camping beaches on both the north and south shore. Several of these beaches have trails that lead up to the glaciers and let you get up close and personal with some deep blue ice.
As far as wildlife goes, I've seen seals, numerous seabirds, bald eagles, and sea lions in the bay. Whales are occasionally seen but for the most part don't venture into the bay due to a shallow moraine.
Overall this is one of the most (if not the most) scenic kayak routes in Alaska and certainly worth the trip for anyone wanting an exciting Alaska kayaking experience.