IMHO
Depends on budget- hotels "in season" in SM can be pricey. Viceroy has very "hip" bar, 1 block from ocean, but I like Shutters better which is 1 block in front of Viceroy, at the ocean, and you can walk up to Viceroy bar.
Stay out of the Marina- that was "hip" in the 80s... and no real "beach" - swimming by where people flush their boats sewers out sucks too.
I have to admit, I'm a "South Bay Bigot" - lived in Hermosa and Manhattan for 20 years. If you have the option, the Beach House in Hermosa is the way to go in summer time- right on beach, tons of bars with young beach crowd (more casual than SM- don't know if that's good or bad for you). And Manhattan Beach has Shade which is extremely popular now with many good restaurants and about 3 blocks from beach.
HTH