Haven't been to Steinhart, but sounds pretty good.
Monterey Bay is worth seeing IMO. I went in '04 (gads, where does the time go .. the days are long but the years are short
) to go see the baby great white they had for a few months. Even only about 36" long, she was "baby white death", man those teeth are something.
Monterey Bay area is quite pretty too, nice coastal scenic drives, etc. Pebble Beach golf course looked nice enough that I'd almost consider playing golf just to see more of it (
)
I say go. You'll likely enjoy it. Plus, it's right next to Cannery Row, so sort of an interesting history to the spot.
You can see sea otters out in the bay, sea lions in the marina, ... pretty humourous as long as you're not one of the boat owners cleaning the sea lion poop off your boat!!